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Audit Complete

Results for https://channel4.com

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SaaS / Software · estimated Tracking: signups
United Stated United Stated · New York Completed: Apr 21, 2026 20:56 UTC
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Mobile 375 × 812

Screenshot of the audited page (Mobile 375×812)

Desktop 1440 × 900

Screenshot of the audited page (Desktop 1440×900)
C70

Site Health

Score: 70 / 100

Based on 8 categories, 0 sections

Room to improve — your 17.5s load time is above Google's 2.5s 'Good' threshold.

Several missing protections leave your users and data exposed.

Several issues make your site difficult for assistive technology users.

Solid SEO basics — a few optimizations could boost rankings.

Solid infrastructure — fast server responses across the board.

Strong compliance posture across regulations.

Missing metadata means poor previews on social media and search.

Heavier than average — reducing page weight saves energy and bandwidth.

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

How the composite score is calculated

How you compare

Amazon Route 53 · 669 peers
You 70
·
Avg 72
At average
0 50 100
Better than 14% of Amazon Route 53 sites See full Amazon Route 53 benchmark →
Boomerang · 107 peers
You 70
·
Avg 72
At average
0 50 100
Better than 17% of Boomerang sites See full Boomerang benchmark →

Top Priorities (5)

1

Content-Security-Policy header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers
2

HSTS header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers
3

No Content-Security-Policy header found

Security gaps expose your site and users to attacks, eroding trust.

Security › Content Security Policy
4

Page weighs 12.0 MB (7.0 MB transferred)

Performance issues directly impact user engagement and conversion rates.

Performance › Page Weight Budget
5

13 link(s) with no accessible text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Link & Button Quality
View fix priority matrix

Fix Priority Matrix

5 findings

Quick Wins

3

High impact, low effort — start here.

Strategic

2

High impact, requires investment.

Easy Improvements

0

Small gains, minimal effort.

Nothing in this quadrant — good news.

Deprioritize

0

Low impact, high effort — do last.

Nothing in this quadrant — good news.

← Low effort High effort →
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What fixing these means

Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Your LCP of 17.5s exceeds Google's 2.5s 'Good' threshold and the 1 performance issue below directly contributes to it. Accessibility issues exclude users who rely on assistive technology — an estimated 15% of your potential audience. Addressing the critical issues below would have the most immediate impact on your user trust.

3 security gaps detected — browsers may warn visitors about your site.
Your LCP is 17.5s — fixing the 1 performance critical could bring it under Google's 2.5s 'Good' threshold.
1 accessibility issue excludes users who rely on assistive technology.

Conversion Barriers

3 critical 6 warning

9 barrier(s) likely increasing bounce by ~33%.

Speed (2)

Page takes 17.5s to load

+12% bounce

Users abandon at ~3s — you're 15.0s over the 2.5s threshold

Fix: Optimize render-blocking resources, preload the hero image, and compress images

Page feels frozen for 1.7s

+5% bounce

Clicks on the primary CTA are ignored while JavaScript runs

Fix: Break up long tasks; defer non-critical JavaScript to post-hydration

Trust (2)

No HSTS header

+1% bounce

Returning visitors are briefly exposed to downgrade attacks on first request

Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains

No Content-Security-Policy header

+1% bounce

Higher XSS blast radius — one compromised script can exfiltrate the checkout form

Fix: Ship a reporting-only CSP first, then enforce once violations are clean

Content (3)

No Open Graph tags

+2% bounce

Links shared on LinkedIn / Slack / Facebook show bare URLs — referral clicks drop

Fix: Add og:title, og:description, og:image, og:url to the page head

No structured data

+2% bounce

No rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices

Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)

Thin content

+3% bounce

Under 300 words — visitors bounce looking for substance, search engines rank competitors first

Fix: Add a substantive FAQ, product detail, or case-study section

Navigation (2)

13 link(s) with generic text ("click here", "read more")

+1% bounce

Screen-reader users navigating by link list see no context — and search engines can't infer relevance

Fix: Rewrite with descriptive phrases that identify the destination

12 broken link(s) on the page

+5% bounce

Clicks land on 404s — trust drops and the session often ends

Fix: Fix or remove the broken destinations surfaced on the Content tab

Preliminary CRO audit — each barrier links to the tab with detailed analysis.

Return on Investment

£375 investment → £1.39/month returns + GBP 50,000 risk avoided

Payback period: > 2 years First-year ROI: -96%

Investment

£375

5h · 5 findings

Monthly returns

£1.39 /mo

~£17 / year

  • Bandwidth savings £1.39

Regulatory risk avoided

GBP 50,000

if kept compliant

  • Equality Act 2010 GBP 50,000

£113 — in quick wins — start here for the fastest payback

Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.

Full methodology & sources

Estimated Remediation Cost

£375

5.0 developer hours at £75/hr

Based on United Kingdom rates (£75/hr)

Quick wins
£113 3 fixes in ~90 minutes

Start here for the best return on investment

Cost by category

Cost by effort level

Adjust assumptions
£ /hr

Rates reflect fully-loaded developer cost including overhead

How developer rates are sourced

What Inaction Is Costing You

£4,168 / month at risk

~£50,017 / year if left unfixed

Compliance Risk

£50,000

Equality Act 2010
  • 3 of 3 <nav> elements are unlabeled
    Equality Act 2010: GBP 500 – GBP 50,000
  • Heading level skipped: H1 → H3 (missing H2)
    Equality Act 2010: GBP 500 – GBP 50,000
  • 6 image-only link(s) without alt text
    Equality Act 2010: GBP 500 – GBP 50,000

Bandwidth Waste

£1.39 /mo

22010.2 MB/mo × 0.063 GBP/GB

  • Optimize transfer: save ~2.2 MB per page load
    Saves £1.39/mo

Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.

Compliance methodology · SEO assumptions · Bandwidth model

Your performance is already good — improvements may show diminishing returns

Unique monthly visitors from your analytics

Purchases, signups, or key actions

Optional — for revenue estimation

additional conversions/month

more engaged visitors from reduced bounce

potential monthly revenue
Current bounce (est.)
After fixes (est.)
Estimated bounce reduction

Fix 5 critical issues to capture this value

How this is calculated

Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.

Your site's LCP: → estimated after fixes.

These are estimates based on industry research — actual results vary

Bounce-rate model & assumptions

Your data stays in your browser — nothing is sent to our servers

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

30
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

8.48 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

17.48 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

1.66 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.003

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

8.48 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

17.57 s

Detailed Report

Audit breakdown by category with detailed findings.

30

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...900.0 s177.0 KiB
cdn.optimizely.com/js/8171642667.js120.0 s134.7 KiB
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...21600.0 s181.1 KiB
/tags/js/v2/eu1-785e164941c9ed4880842cc0c6d6bf0c/mparticl...3600.0 s58.3 KiB
static.channel4.com/all4-dtm/latest/dtm.js900.0 s46.5 KiB
www.channel4.com/staticfonts/latest/c4.text/punctuation.woff3600.0 s32.4 KiB
www.channel4.com/staticfonts/latest/c4.headline/punctuation.woff3600.0 s28.9 KiB
www.channel4.com/staticfonts/latest/4text.medium/punctuation.woff3600.0 s22.4 KiB
www.channel4.com/staticfonts/latest/4text.medium/lowercase.woff3600.0 s22.4 KiB
www.channel4.com/staticfonts/latest/4text.regular/punctuation.woff3600.0 s22.1 KiB
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...900.0 s13.2 KiB
www.channel4.com/consent/loader.js?mountpoint=cookie-consent-banner872.0 s11.3 KiB
s.go-mpulse.net/boomerang/XF74S-NBRPP-BVVGB-BSCMM-3V6RK604800.0 s56.1 KiB
static.c4assets.com/all4-ad-code/latest/adverts.js900.0 s6.0 KiB
mssl.fwmrm.net/p/c4_display/LinkTag2.js?0.0 ms2.7 KiB
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...900.0 s2.1 KiB
/maze-universal-loader.js?apiKey=4f48c7e5-f420-4f3d-8fcf-...43200.0 s2.7 KiB
/all4-dtm/latest/b8b3c372794b/RC1ccad7261ae1404ba561eefcb...900.0 s1.1 KiB
/all4-dtm/latest/b8b3c372794b/RC4eee81b06a674aa790a559fd9...900.0 s1016 B
/all4-dtm/latest/b8b3c372794b/RC20d7ca4abe3547efb0eeb64d7...900.0 s998 B
/all4-dtm/latest/b8b3c372794b/RC0215f20884cf4ddcabe4edd10...900.0 s877 B
//stylesheet?c4.text&c4.headline&c4.medium&4text.regular&...2297.0 s835 B
/stylesheet?4text.regular&4text.medium&4headline.extrabol...1011.0 s692 B
cdn-pci.optimizely.com/js/geo4.js0.0 ms512 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:66.868 source:map[column:824689 line:2 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:0.496 source:map[column:362557 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:28.936 source:map[column:636100 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:14.281 source:map[column:1.165333e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:8.242 source:map[column:1.160058e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:14.913 source:map[column:1.276285e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:0.743 source:map[column:1.407828e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:20.189 source:map[column:1.096946e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
https://ic.c4assets.com/bips/collections/308ECADF-32C0-4cdd-816d-0cf472a03761.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/308ECADF-32C0-4cdd-816d-0cf472a03761.jp...143.4 KiB135.9 KiB
https://ic.c4assets.com/bips/collections/7BACA07E-A75A-4488-af69-6793f8aaf513.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
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https://ic.c4assets.com/bips/collections/636E1505-8206-48e0-9388-4e2582576733.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/3298CAAC-2922-407e-89c7-62361c5cb9be.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
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https://ic.c4assets.com/bips/collections/ae66ff38-6476-447e-b788-41cd8beb0604.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/DC649EF1-68DE-4ce8-b3f4-3fd36ca89ba8.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/EB5D8ABF-1D0B-48cf-b32c-c67b3cdc0018.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/8AC1592D-05EE-4588-887f-788c8d906a2a.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/F84D84C5-1A6C-42be-abc4-7de72bd603a0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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Your Song div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper > div.all4-superhero-slice__hero-content > img.all4-superhero-slice__hero__title
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h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
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Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]
items: [map[duration:382.188 label:Time to first byte subpart:timeToFirstByte] map[duration:1651.234 label:Resource load delay subpart:resourceLoadDelay] map[duration:60.754 label:Resource load duration subpart:resourceLoadDuration] map[duration:585.593 label:Element render delay subpart:elementRenderDelay]]
lhId: page-54-IMG
nodeLabel: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
path: 1,HTML,1,BODY,5,DIV,2,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,SECTION,0,IMG
selector: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
snippet: <img alt="" src="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" srcset="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" sizes="(min-width: 3840px) 100vw, (min-width: 2160px) 100vw, (min-width: 1920px) …" loading="eager">

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-54-IMG
nodeLabel: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
path: 1,HTML,1,BODY,5,DIV,2,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,SECTION,0,IMG
selector: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
snippet: <img alt="" src="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" srcset="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" sizes="(min-width: 3840px) 100vw, (min-width: 2160px) 100vw, (min-width: 1920px) …" loading="eager">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.
description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 991 ms
URLTime Spent
channel4.com/991 ms
www.channel4.com/0.0 ms

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 20.0 KiB
URLTransfer SizeEst Savings
cdn.optimizely.com/js/8171642667.js134.1 KiB20.0 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 600 ms 65.8 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation5.6 s
Other1.5 s
Style & Layout859 ms
Script Parsing & Compilation568 ms
Garbage Collection254 ms
Rendering231 ms
Parse HTML & CSS67 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
The page has an unload handler in a sub frame.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
Your Song div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper > div.all4-superhero-slice__hero-content > img.all4-superhero-slice__hero__title
/bips/159381/44CD9E43-00D4-4308-92c0-12b162690b7f.png?imf...
div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.jpg?imf...
Channel4.com Homepage li.nav__list__item > a#all4-logo > div.nav__list__item__link__content > img.all4gn__home-image
all4nav.channel4.com/globalnav/static/2.1.34/images/all4_logo.svg
Sign in li.nav__list__item > a.nav__list__item__link > div.nav__list__item__link__content > img.signIn-icon
all4nav.channel4.com/globalnav/static/2.1.34/images/account_icon.svg
Search li.nav__list__item > a.nav__list__item__link > div.nav__list__item__link__content > img.search-icon
all4nav.channel4.com/globalnav/static/2.1.34/images/search_icon.svg

More information about the performance of your application. These numbers don't directly affect the Performance score.

Layout shift culprits
Optimize DOM size
Optimize viewport for mobile
Minify CSS
User Timing marks and measures 2 user timings
Avoid long main-thread tasks 20 long tasks found
Network Requests
Network Round Trip Times 80 ms
Server Backend Latencies 520 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Initial server response time was short Root document took 110 ms
Avoid large layout shifts 2 layout shifts found
INP breakdown
Avoid non-composited animations
96

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

ARIA

ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. Learn how to make ARIA dialog elements more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Your privacy on Channel 4 We use cookies on your device to help us provide a mo… body.touch > div#cookie-consent-banner > div
Your privacy on Channel 4 We use cookies on your device to help us provide a mo… body.touch > div#cookie-consent-banner > div > div.cookie-banner

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Accept & Continue div.all4-cc-grid > div.all4-cc-popup__content-area > div.all4-cc-grid > button.all4-cc-primary-button
Reject & Continue div.all4-cc-grid > div.all4-cc-popup__content-area > div.all4-cc-grid > button.all4-cc-secondary-button
Ordinary people perform the song that tells their extraordinary story div > div.all4-superhero-slice > div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Made in Chelsea Reality series following the lives, loves and awks of SW3's br… div.swiper-slide > div.block > div.block__content > a.block__link
The Copenhagen Test Spy thriller. Intelligence analyst Alexander Hale realises… div.swiper-slide > div.block > div.block__content > a.block__link
Suez: 24 Hours That… The dramatic inside story of the Suez Crisis, which chang… div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
The drama starts here The biggest and best dramas from the UK, the US and beyo… div.swiper-slide > div.block > div.block__content > a.block__link
A Woman of Substance Epic rags-to-riches saga of Emma Harte’s rise from housem… div.swiper-slide > div.block > div.block__content > a.block__link
It's A Sin Drama from Russell T Davies about five friends living and loving in… div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Click here for Comedy All-you-can-eat comedy! Get stuck in. div.swiper-slide > div.block > div.block__content > a.block__link
The Inbetweeners Smash-hit adolescent comedy about a bunch of lads behaving sa… div.swiper-slide > div.block > div.block__content > a.block__link
Big Mood Maggie's bipolar disorder puts her friendship with bestie Eddie to th… div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Find a new favourite Great films you know, great films you don't div.swiper-slide > div.block > div.block__content > a.block__link
Plane (2023) Action with Gerard Butler. A pilot crash-lands on an island full … div.swiper-slide > div.block > div.block__content > a.block__link
Sonic the Hedgehog (2020) Madcap adventure-comedy adaptation of the iconic vid… div.swiper-slide > div.block > div.block__content > a.block__link
Interactive controls are keyboard focusable
Interactive elements indicate their purpose and state
The page has a logical tab order
Visual order on the page follows DOM order
User focus is not accidentally trapped in a region
The user's focus is directed to new content added to the page
HTML5 landmark elements are used to improve navigation
Offscreen content is hidden from assistive technology
Custom controls have associated labels
Custom controls have ARIA roles
`[aria-*]` attributes match their roles
`[aria-hidden="true"]` is not present on the document `<body>`
`[role]`s have all required `[aria-*]` attributes
`[role]` values are valid
`[aria-*]` attributes have valid values
`[aria-*]` attributes are valid and not misspelled
Buttons have an accessible name
Image elements have `[alt]` attributes
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
`button`, `link`, and `menuitem` elements have accessible names
ARIA attributes are used as specified for the element's role
`[aria-hidden="true"]` elements do not contain focusable descendents
Elements use only permitted ARIA attributes
Background and foreground colors have a sufficient contrast ratio
Document has a `<title>` element
`<html>` element has a `[lang]` attribute
`<html>` element has a valid value for its `[lang]` attribute
Links have a discernible name
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
No element has a `[tabindex]` value greater than 0
Touch targets have sufficient size and spacing.
Heading elements appear in a sequentially-descending order
Document has a main landmark.
Deprecated ARIA roles were not used
Identical links have the same purpose.
`[accesskey]` values are unique
ARIA input fields have accessible names
ARIA `meter` elements have accessible names
ARIA `progressbar` elements have accessible names
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
`[role]`s are contained by their required parent element
Elements with the `role=text` attribute do not have focusable descendents.
ARIA toggle fields have accessible names
ARIA `tooltip` elements have accessible names
ARIA `treeitem` elements have accessible names
The page contains a heading, skip link, or landmark region
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Definition list items are wrapped in `<dl>` elements
ARIA IDs are unique
No form fields have multiple labels
`<frame>` or `<iframe>` elements have a title
`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
Input buttons have discernible text.
`<input type="image">` elements have `[alt]` text
Form elements have associated labels
Links are distinguishable without relying on color.
The document does not use `<meta http-equiv="refresh">`
`<object>` elements have alternate text
Select elements have associated label elements.
Skip links are focusable.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
`[lang]` attributes have a valid value
`<video>` elements contain a `<track>` element with `[kind="captions"]`
Tables have different content in the summary attribute and `<caption>`.
All heading elements contain content.
Uses ARIA roles only on compatible elements
Image elements do not have `[alt]` attributes that are redundant text.
Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
`<td>` elements in a large `<table>` have one or more table headers.
77

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
Unload event listeners are deprecated and will be removed.

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

SourceDescription
Failed to load resource: net::ERR_CERT_COMMON_NAME_INVALID

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uses HTTPS
Avoids third-party cookies
Allows users to paste into input fields
Avoids requesting the geolocation permission on page load
Avoids requesting the notification permission on page load
Displays images with correct aspect ratio
Serves images with appropriate resolution
Page has the HTML doctype
Properly defines charset
No issues in the `Issues` panel in Chrome Devtools
Ensure CSP is effective against XSS attacks
Use a strong HSTS policy
Ensure proper origin isolation with COOP
Mitigate DOM-based XSS with Trusted Types
Detected JavaScript libraries
Redirects HTTP traffic to HTTPS
Mitigate clickjacking with XFO or CSP
100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Structured data is valid
Page isn’t blocked from indexing
Document has a `<title>` element
Document has a meta description
Page has successful HTTP status code
Links have descriptive text
Links are crawlable
robots.txt is valid
Image elements have `[alt]` attributes
Document has a valid `hreflang`
Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

60
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.45 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

3.65 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

257 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.018

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

2.79 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

3.66 s

Detailed Report

Audit breakdown by category with detailed findings.

60

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...900.0 s176.9 KiB
cdn.optimizely.com/js/8171642667.js120.0 s134.7 KiB
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...21600.0 s178.1 KiB
/tags/js/v2/eu1-785e164941c9ed4880842cc0c6d6bf0c/mparticl...3600.0 s58.3 KiB
static.channel4.com/all4-dtm/latest/dtm.js900.0 s46.5 KiB
www.channel4.com/staticfonts/latest/c4.text/punctuation.woff3600.0 s32.4 KiB
www.channel4.com/staticfonts/latest/c4.headline/punctuation.woff3600.0 s28.8 KiB
www.channel4.com/staticfonts/latest/4text.medium/punctuation.woff3600.0 s22.4 KiB
www.channel4.com/staticfonts/latest/4text.medium/lowercase.woff3600.0 s22.4 KiB
www.channel4.com/staticfonts/latest/4text.regular/punctuation.woff3600.0 s22.1 KiB
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...900.0 s13.2 KiB
www.channel4.com/consent/loader.js?mountpoint=cookie-consent-banner848.0 s11.3 KiB
s.go-mpulse.net/boomerang/XF74S-NBRPP-BVVGB-BSCMM-3V6RK604800.0 s56.1 KiB
static.c4assets.com/all4-ad-code/latest/adverts.js900.0 s6.0 KiB
mssl.fwmrm.net/p/c4_display/LinkTag2.js?0.0 ms2.7 KiB
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...900.0 s2.1 KiB
/maze-universal-loader.js?apiKey=4f48c7e5-f420-4f3d-8fcf-...43200.0 s2.7 KiB
/all4-dtm/latest/b8b3c372794b/RC1ccad7261ae1404ba561eefcb...900.0 s1.1 KiB
/all4-dtm/latest/b8b3c372794b/RC4eee81b06a674aa790a559fd9...900.0 s1016 B
/all4-dtm/latest/b8b3c372794b/RC20d7ca4abe3547efb0eeb64d7...900.0 s998 B
/all4-dtm/latest/b8b3c372794b/RC0215f20884cf4ddcabe4edd10...900.0 s877 B
//stylesheet?c4.text&c4.headline&c4.medium&4text.regular&...1903.0 s835 B
/stylesheet?4text.regular&4text.medium&4headline.extrabol...3529.0 s692 B
cdn-pci.optimizely.com/js/geo4.js0.0 ms489 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:36.225 source:map[column:824689 line:2 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:1.211 source:map[type:text value:[unattributed]]] map[reflowTime:12.152 source:map[column:1.407828e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:0.589 source:map[column:362557 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:29.347 source:map[column:636100 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:6.289 source:map[column:1.165333e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
https://ic.c4assets.com/bips/collections/7BACA07E-A75A-4488-af69-6793f8aaf513.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7BACA07E-A75A-4488-af69-6793f8aaf513.jp...131.1 KiB110.6 KiB
https://ic.c4assets.com/bips/collections/A6E7BB13-7B0F-416c-ad98-d641798270fd.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A6E7BB13-7B0F-416c-ad98-d641798270fd.jp...124.4 KiB104.0 KiB
https://ic.c4assets.com/bips/collections/A6E7BB13-7B0F-4ace-aa88-91008c1aceb2.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A6E7BB13-7B0F-4ace-aa88-91008c1aceb2.jp...124.4 KiB104.0 KiB
https://ic.c4assets.com/bips/collections/0692B70D-66BA-403c-884b-f42195cc5649.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/0692B70D-66BA-403c-884b-f42195cc5649.jp...117.8 KiB97.4 KiB
https://ic.c4assets.com/bips/collections/CFA6B2CC-7233-4148-9e88-9bc888a62777.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/CFA6B2CC-7233-4148-9e88-9bc888a62777.jp...102.3 KiB81.9 KiB
https://ic.c4assets.com/bips/collections/8014C3A9-6A72-489f-9992-1f2d503b30e0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/8014C3A9-6A72-489f-9992-1f2d503b30e0.jp...96.8 KiB76.4 KiB
https://ic.c4assets.com/bips/collections/32E9F07C-BFDD-4380-8000-07223b5373d9.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/32E9F07C-BFDD-4380-8000-07223b5373d9.jp...96.4 KiB76.0 KiB
https://ic.c4assets.com/bips/collections/08BAC8A6-DE84-403f-b94d-243727fd16bf.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/08BAC8A6-DE84-403f-b94d-243727fd16bf.jp...95.2 KiB74.7 KiB
https://ic.c4assets.com/bips/collections/7C769E31-1996-483e-9781-6ea1795863c7.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7C769E31-1996-483e-9781-6ea1795863c7.jp...94.6 KiB74.2 KiB
https://ic.c4assets.com/bips/collections/8F146414-0E74-4177-bde6-e6f6b7f6e57b.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/8F146414-0E74-4177-bde6-e6f6b7f6e57b.jp...93.4 KiB72.9 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/1A0581A2-35BB-47ef-80da-f28eae25d0e9.jp...80.2 KiB71.8 KiB
https://ic.c4assets.com/bips/collections/B8E9F339-E08F-41be-a1f1-bcd555c33574.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/B8E9F339-E08F-41be-a1f1-bcd555c33574.jp...90.6 KiB70.2 KiB
https://ic.c4assets.com/bips/collections/35EBF852-EE30-4c78-a7ee-2b680dd9d419.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/35EBF852-EE30-4c78-a7ee-2b680dd9d419.jp...86.8 KiB66.3 KiB
https://ic.c4assets.com/bips/collections/A4E55A49-6D91-43fb-9330-dfcbd90c6849.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A4E55A49-6D91-43fb-9330-dfcbd90c6849.jp...82.8 KiB62.3 KiB
https://ic.c4assets.com/bips/collections/F57743AC-A9E3-4610-84e4-179ac57fb298.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/F57743AC-A9E3-4610-84e4-179ac57fb298.jp...82.3 KiB61.9 KiB
https://ic.c4assets.com/bips/collections/DE1CE5C4-FE03-4c24-8719-f8d0972967c0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/387793B0-9B13-4ed2-b7cb-5019d9d31df8.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/387793B0-9B13-4ed2-b7cb-5019d9d31df8.jp...79.4 KiB59.0 KiB
https://ic.c4assets.com/bips/collections/43bca549-afe5-47f0-addd-c4998352b095.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/43bca549-afe5-47f0-addd-c4998352b095.jp...78.5 KiB58.0 KiB
https://ic.c4assets.com/bips/collections/723348F2-C6A7-4696-851a-7b4cf2cbab4a.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/723348F2-C6A7-4696-851a-7b4cf2cbab4a.jp...78.5 KiB58.0 KiB
https://ic.c4assets.com/bips/collections/0497BDC0-EC0A-4902-b11f-1b82e76d726b.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/0497BDC0-EC0A-4902-b11f-1b82e76d726b.jp...78.3 KiB57.9 KiB
https://ic.c4assets.com/bips/collections/423E11FA-DD2D-4913-94c9-adc4d821a64d.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/423E11FA-DD2D-4913-94c9-adc4d821a64d.jp...78.2 KiB57.7 KiB
https://ic.c4assets.com/bips/collections/B661E3B6-7A74-4510-a208-66b57f4e4594.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/B661E3B6-7A74-4510-a208-66b57f4e4594.jp...78.0 KiB57.5 KiB
https://ic.c4assets.com/bips/collections/B967A0C8-41B3-4378-9e69-2162b71ca321.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/B967A0C8-41B3-4378-9e69-2162b71ca321.jp...70.5 KiB50.0 KiB
https://ic.c4assets.com/bips/collections/9E054421-DD3C-440f-9804-9b4fabad3592.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/9E054421-DD3C-440f-9804-9b4fabad3592.jp...70.3 KiB49.9 KiB
https://ic.c4assets.com/bips/collections/3DC47AAE-3E7F-406a-8460-20d7ade0f132.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/3DC47AAE-3E7F-406a-8460-20d7ade0f132.jp...68.2 KiB47.7 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/B577486A-7450-47e3-b61e-8e847d65aeeb.jp...52.6 KiB44.2 KiB
https://ic.c4assets.com/bips/collections/35353A7B-989D-42c3-9910-939454584ca5.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/35353A7B-989D-42c3-9910-939454584ca5.jp...64.1 KiB43.7 KiB
https://ic.c4assets.com/bips/collections/35353A7B-989D-4661-985d-9a50ee840787.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/35353A7B-989D-4661-985d-9a50ee840787.jp...64.1 KiB43.7 KiB
https://ic.c4assets.com/bips/collections/60AFF2DA-B5F1-44d4-a7cd-32fe083f78de.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/60AFF2DA-B5F1-44d4-a7cd-32fe083f78de.jp...62.6 KiB42.2 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/08580D8B-3BCE-4eb2-ab99-15b41b831b7d.jp...45.7 KiB37.2 KiB
https://ic.c4assets.com/bips/collections/17D6DFC0-C203-4d94-a9b7-518582febcf1.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/17D6DFC0-C203-4d94-a9b7-518582febcf1.jp...57.5 KiB37.0 KiB
https://ic.c4assets.com/bips/collections/E3F30F51-1978-4520-b00a-a3a6a7055970.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/E3F30F51-1978-4520-b00a-a3a6a7055970.jp...56.5 KiB36.1 KiB
https://ic.c4assets.com/bips/collections/7D6A57DF-C8D9-4593-9456-9a8d2cecf204.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7D6A57DF-C8D9-4593-9456-9a8d2cecf204.jp...49.8 KiB31.4 KiB
https://ic.c4assets.com/bips/collections/388B966E-5AD4-4ed9-9948-0c0c05d918e7.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/388B966E-5AD4-4ed9-9948-0c0c05d918e7.jp...49.6 KiB31.3 KiB
https://ic.c4assets.com/bips/collections/3298CAAC-2922-407e-89c7-62361c5cb9be.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/3298CAAC-2922-407e-89c7-62361c5cb9be.jp...49.4 KiB31.2 KiB
Your Song div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper > div.all4-superhero-slice__hero-content > img.all4-superhero-slice__hero__title
/bips/159381/44CD9E43-00D4-4308-92c0-12b162690b7f.png?imf...30.2 KiB28.1 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/C410205C-42E1-41fd-bb48-74b58861bb33.jp...34.5 KiB28.0 KiB
https://ic.c4assets.com/bips/collections/DC649EF1-68DE-4ce8-b3f4-3fd36ca89ba8.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/DC649EF1-68DE-4ce8-b3f4-3fd36ca89ba8.jp...42.5 KiB26.8 KiB
https://ic.c4assets.com/bips/collections/4C51C13E-F5D6-486d-9aad-43aee3935f83.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/4C51C13E-F5D6-486d-9aad-43aee3935f83.jp...35.2 KiB22.2 KiB
https://ic.c4assets.com/bips/collections/F84D84C5-1A6C-42be-abc4-7de72bd603a0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/F84D84C5-1A6C-42be-abc4-7de72bd603a0.jp...34.2 KiB21.6 KiB
https://ic.c4assets.com/bips/collections/C92D6B29-8AE6-46c9-84fd-b7d200f33027.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/C92D6B29-8AE6-46c9-84fd-b7d200f33027.jp...32.3 KiB20.4 KiB
https://ic.c4assets.com/bips/collections/FAFE6B76-D9D9-4c67-be98-37e5a298b28d.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/FAFE6B76-D9D9-4c67-be98-37e5a298b28d.jp...30.1 KiB19.0 KiB
div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.jpg?imf...148.1 KiB17.9 KiB
https://ic.c4assets.com/bips/collections/3F707659-A8D2-4c5c-a479-9502ae32a3c5.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-42-IMG
nodeLabel: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
path: 1,HTML,1,BODY,5,DIV,2,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,SECTION,0,IMG
selector: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
snippet: <img alt="" src="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" srcset="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" sizes="(min-width: 3840px) 100vw, (min-width: 2160px) 100vw, (min-width: 1920px) …" loading="eager">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.
description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 441 ms
URLTime Spent
channel4.com/441 ms
www.channel4.com/0.0 ms

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 20.0 KiB
URLTransfer SizeEst Savings
cdn.optimizely.com/js/8171642667.js134.1 KiB20.0 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 70 ms 64.6 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation1.4 s
Other318 ms
Style & Layout189 ms
Script Parsing & Compilation141 ms
Garbage Collection42 ms
Rendering37 ms
Parse HTML & CSS16 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
The page has an unload handler in a sub frame.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.jpg?imf...
Your Song div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper > div.all4-superhero-slice__hero-content > img.all4-superhero-slice__hero__title
/bips/159381/44CD9E43-00D4-4308-92c0-12b162690b7f.png?imf...
Channel4.com Homepage li.nav__list__item > a#all4-logo > div.nav__list__item__link__content > img.all4gn__home-image
all4nav.channel4.com/globalnav/static/2.1.34/images/all4_logo.svg
Sign in li.nav__list__item > a.nav__list__item__link > div.nav__list__item__link__content > img.signIn-icon
all4nav.channel4.com/globalnav/static/2.1.34/images/account_icon.svg
Search li.nav__list__item > a.nav__list__item__link > div.nav__list__item__link__content > img.search-icon
all4nav.channel4.com/globalnav/static/2.1.34/images/search_icon.svg

More information about the performance of your application. These numbers don't directly affect the Performance score.

Layout shift culprits
Optimize DOM size
LCP breakdown
Optimize viewport for mobile
Minify CSS
User Timing marks and measures 2 user timings
Avoid long main-thread tasks 5 long tasks found
Network Requests
Network Round Trip Times 80 ms
Server Backend Latencies 210 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Initial server response time was short Root document took 140 ms
Avoid large layout shifts 4 layout shifts found
INP breakdown
Avoid non-composited animations
96

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

ARIA

ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. Learn how to make ARIA dialog elements more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Your privacy on Channel 4 We use cookies on your device to help us provide a mo… body.no-touch > div#cookie-consent-banner > div
Your privacy on Channel 4 We use cookies on your device to help us provide a mo… body.no-touch > div#cookie-consent-banner > div > div.cookie-banner

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Accept & Continue div.all4-cc-grid > div.all4-cc-popup__content-area > div.all4-cc-grid > button.all4-cc-primary-button
Reject & Continue div.all4-cc-grid > div.all4-cc-popup__content-area > div.all4-cc-grid > button.all4-cc-secondary-button
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Made in Chelsea Reality series following the lives, loves and awks of SW3's br… div.swiper-slide > div.block > div.block__content > a.block__link
The Copenhagen Test Spy thriller. Intelligence analyst Alexander Hale realises… div.swiper-slide > div.block > div.block__content > a.block__link
Suez: 24 Hours That Broke the British… The dramatic inside story of the Suez C… div.swiper-slide > div.block > div.block__content > a.block__link
24 Hours in Police Custody The landmark series that follows police detectives … div.swiper-slide > div.block > div.block__content > a.block__link
Bergerac A modern re-imagining of the iconic Jersey-set crime drama following … div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
The drama starts here The biggest and best dramas from the UK, the US and beyo… div.swiper-slide > div.block > div.block__content > a.block__link
A Woman of Substance Epic rags-to-riches saga of Emma Harte’s rise from housem… div.swiper-slide > div.block > div.block__content > a.block__link
It's A Sin Drama from Russell T Davies about five friends living and loving in… div.swiper-slide > div.block > div.block__content > a.block__link
Patience Crime drama. Talented autistic archivist Patience enters an unpredict… div.swiper-slide > div.block > div.block__content > a.block__link
The Copenhagen Test Spy thriller. Intelligence analyst Alexander Hale realises… div.swiper-slide > div.block > div.block__content > a.block__link
Interactive controls are keyboard focusable
Interactive elements indicate their purpose and state
The page has a logical tab order
Visual order on the page follows DOM order
User focus is not accidentally trapped in a region
The user's focus is directed to new content added to the page
HTML5 landmark elements are used to improve navigation
Offscreen content is hidden from assistive technology
Custom controls have associated labels
Custom controls have ARIA roles
`[aria-*]` attributes match their roles
`[aria-hidden="true"]` is not present on the document `<body>`
`[role]`s have all required `[aria-*]` attributes
`[role]` values are valid
`[aria-*]` attributes have valid values
`[aria-*]` attributes are valid and not misspelled
Buttons have an accessible name
Image elements have `[alt]` attributes
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
`button`, `link`, and `menuitem` elements have accessible names
ARIA attributes are used as specified for the element's role
`[aria-hidden="true"]` elements do not contain focusable descendents
Elements use only permitted ARIA attributes
Background and foreground colors have a sufficient contrast ratio
Document has a `<title>` element
`<html>` element has a `[lang]` attribute
`<html>` element has a valid value for its `[lang]` attribute
Links have a discernible name
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
No element has a `[tabindex]` value greater than 0
Touch targets have sufficient size and spacing.
Heading elements appear in a sequentially-descending order
Document has a main landmark.
Deprecated ARIA roles were not used
Identical links have the same purpose.
`[accesskey]` values are unique
ARIA input fields have accessible names
ARIA `meter` elements have accessible names
ARIA `progressbar` elements have accessible names
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
`[role]`s are contained by their required parent element
Elements with the `role=text` attribute do not have focusable descendents.
ARIA toggle fields have accessible names
ARIA `tooltip` elements have accessible names
ARIA `treeitem` elements have accessible names
The page contains a heading, skip link, or landmark region
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Definition list items are wrapped in `<dl>` elements
ARIA IDs are unique
No form fields have multiple labels
`<frame>` or `<iframe>` elements have a title
`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
Input buttons have discernible text.
`<input type="image">` elements have `[alt]` text
Form elements have associated labels
Links are distinguishable without relying on color.
The document does not use `<meta http-equiv="refresh">`
`<object>` elements have alternate text
Select elements have associated label elements.
Skip links are focusable.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
`[lang]` attributes have a valid value
`<video>` elements contain a `<track>` element with `[kind="captions"]`
Tables have different content in the summary attribute and `<caption>`.
All heading elements contain content.
Uses ARIA roles only on compatible elements
Image elements do not have `[alt]` attributes that are redundant text.
Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
`<td>` elements in a large `<table>` have one or more table headers.
77

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
Unload event listeners are deprecated and will be removed.

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

SourceDescription
Failed to load resource: net::ERR_CERT_COMMON_NAME_INVALID

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uses HTTPS
Avoids third-party cookies
Allows users to paste into input fields
Avoids requesting the geolocation permission on page load
Avoids requesting the notification permission on page load
Displays images with correct aspect ratio
Serves images with appropriate resolution
Page has the HTML doctype
Properly defines charset
No issues in the `Issues` panel in Chrome Devtools
Ensure CSP is effective against XSS attacks
Use a strong HSTS policy
Ensure proper origin isolation with COOP
Mitigate DOM-based XSS with Trusted Types
Detected JavaScript libraries
Redirects HTTP traffic to HTTPS
Mitigate clickjacking with XFO or CSP
100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Structured data is valid
Page isn’t blocked from indexing
Document has a `<title>` element
Document has a meta description
Page has successful HTTP status code
Links have descriptive text
Links are crawlable
robots.txt is valid
Image elements have `[alt]` attributes
Document has a valid `hreflang`
Document has a valid `rel=canonical`

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