Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Detailed Report

Audit breakdown by category with detailed findings.

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

Performance issues directly impact user engagement and conversion rates.

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.

Request	Cache TTL	Transfer Size
www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416	0.0 ms	309.3 KiB
www.lrb.co.uk/lrb_assets/build/css/main.css?v=20260416	0.0 ms	63.4 KiB
www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416	0.0 ms	56.2 KiB
www.lrb.co.uk/lrb_assets/images/icons/lrb-loading.gif	172800.0 s	154.2 KiB
cdn.consentmanager.net/delivery/js/cmp_final.min.js?t=2026-4-22	86400.0 s	100.9 KiB
/storage/800_filter/images/2/4/7/1/31071742-1-eng-GB/51a0...	172800.0 s	101.1 KiB
www.lrb.co.uk/lrb_assets/fonts/QuadraatPro-Bold.woff2	172800.0 s	51.4 KiB
www.lrb.co.uk/lrb_assets/fonts/QuadraatPro.woff2	172800.0 s	50.6 KiB
www.lrb.co.uk/lrb_assets/fonts/QuadraatPro-Ita.woff2	172800.0 s	47.9 KiB
www.lrb.co.uk/lrb_assets/fonts/IdealSans-LightItalic.woff2	172800.0 s	33.9 KiB
www.lrb.co.uk/lrb_assets/fonts/IdealSans-Light.woff2	172800.0 s	32.9 KiB
www.lrb.co.uk/lrb_assets/fonts/IdealSans-Medium.woff2	172800.0 s	32.7 KiB
cdn.speedcurve.com/js/lux.js?id=4344563349	3600.0 s	11.3 KiB
www.lrb.co.uk/lrb_assets/fonts/IdealSans-Book.woff2	172800.0 s	30.1 KiB
/delivery/customdata/bV8xLndfMTQ0OTIzLnJfR0RQUi5sX2VuLmRf...	3600.0 s	9.5 KiB
js.sentry-cdn.com/df903b546d604809adfeedb11b4f6c10.min.js	3600.0 s	2.7 KiB
stats.lrb.co.uk/hello.js	0.0 ms	1.9 KiB
www.lrb.co.uk/lrb_assets/build/images/book-icon.2f785f35.svg	172800.0 s	880 B
www.lrb.co.uk/lrb_assets/build/images/lrb-monogram-faded.2ae3ec58.svg	172800.0 s	811 B

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]

items: [map[node:map[type:text value:Total] score:0.119077] map[node:map[boundingRect:map[bottom:823 height:823 left:0 right:412 top:0 width:412] lhId:page-1-BODY nodeLabel:body.section-home path:1,HTML,1,BODY selector:body.section-home snippet:<body class="section-home " style="height: 100%; overflow: hidden;"> type:node] score:0.119077]]

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:54.658 source:map[column:24875 line:2 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416 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:0.272 source:map[column:161522 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:0.159 source:map[column:161580 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:0.151 source:map[column:161644 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:26.568 source:map[column:160846 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:0.21 source:map[column:31269 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416 urlProvider:network]] map[reflowTime:0.295 source:map[column:162473 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:0.55 source:map[column:160868 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:0.228 source:map[column:198668 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416 urlProvider:network]] map[reflowTime:2.332 source:map[column:787705 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:15.276 source:map[column:787862 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:9.045 source:map[column:788024 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416 urlProvider:network]] map[reflowTime:1.837 source:map[column:197977 line:1 type:source-location url:https://www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416 urlProvider:network]]]

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:210.455 label:Time to first byte subpart:timeToFirstByte] map[duration:1154.347 label:Resource load delay subpart:resourceLoadDelay] map[duration:4.864 label:Resource load duration subpart:resourceLoadDuration] map[duration:1470.69 label:Element render delay subpart:elementRenderDelay]]

lhId: page-0-A

nodeLabel: div.article-link-block--default > div.inner > div.image-content > a.article-link-block--image

path: 1,HTML,1,BODY,18,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,A

selector: div.article-link-block--default > div.inner > div.image-content > a.article-link-block--image

snippet: <a href="/the-paper/v48/n07/ian-penman/i-m-just-a-sound" class="article-link-block--image lazypreload lazyloaded" data-bgset="https://www.lrb.co.uk/storage/300_filter/images/2/4/7/1/31071742-1-eng-GB/…" style="background-image: url("https://www.lrb.co.uk/storage/800_filter/images/2/4…");">

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-0-A

nodeLabel: div.article-link-block--default > div.inner > div.image-content > a.article-link-block--image

path: 1,HTML,1,BODY,18,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,A

selector: div.article-link-block--default > div.inner > div.image-content > a.article-link-block--image

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.

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.

URL	Transfer Size	Duration
www.lrb.co.uk/lrb_assets/build/css/main.css?v=20260416	63.4 KiB	453 ms

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.

URL	Est Savings
www.lrb.co.uk/lrb_assets/fonts/IdealSans-Book.woff2	10 ms
www.lrb.co.uk/lrb_assets/fonts/QuadraatPro-Bold.woff2	10 ms
www.lrb.co.uk/lrb_assets/fonts/IdealSans-LightItalic.woff2	10 ms
www.lrb.co.uk/lrb_assets/fonts/QuadraatPro-Ita.woff2	5.0 ms

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.

	URL	Resource Size	Est Savings
div.article-link-block--default > div.inner > div.image-content > a.article-link-block--image `div.article-link-block--default > div.inner > div.image-content > a.article-link-block--image`	/storage/800_filter/images/2/4/7/1/31071742-1-eng-GB/51a0...	100.7 KiB	26.6 KiB

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: 751 ms

URL	Time Spent
lrb.co.uk/	751 ms
www.lrb.co.uk/	0.0 ms

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

Why this matters

Performance issues directly impact user engagement and conversion rates.

Element	Layout shift score
body.section-home `body.section-home`	0.119

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

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: 300 ms 91.2 KiB

URL	Transfer Size	Est Savings
www.lrb.co.uk/lrb_assets/build/css/main.css?v=20260416	63.1 KiB	53.7 KiB
a,abbr,acronym,address,applet,article,aside,audio,b,big,b...	53.6 KiB	37.5 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

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 2.7 s 625.4 KiB

URL	Transfer Size	Est Savings
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js	361.8 KiB	243.0 KiB
www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416	298.2 KiB	220.5 KiB
www.googletagmanager.com/gtag/js?id=G-JE69ELWJLM	171.6 KiB	66.0 KiB
cdn.consentmanager.net/delivery/js/cmp_final.min.js?t=2026-4-22	100.4 KiB	36.2 KiB
www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416	56.2 KiB	31.1 KiB
browser.sentry-cdn.com/10.49.0/bundle.tracing.replay.min.js	80.4 KiB	28.6 KiB

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.

URL	Total CPU Time	Script Evaluation	Script Parse
www.lrb.co.uk/lrb_assets/build/js/main.js?v=20260416	1.4 s	877 ms	17 ms
www.lrb.co.uk/	733 ms	165 ms	6.4 ms
js.sentry-cdn.com/df903b546d604809adfeedb11b4f6c10.min.js	486 ms	481 ms	0.5 ms
www.lrb.co.uk/lrb_assets/build/js/vendor.js?v=20260416	345 ms	156 ms	98 ms
Unattributable	278 ms	15 ms	0.0 ms
browser.sentry-cdn.com/10.49.0/bundle.tracing.replay.min.js	256 ms	212 ms	18 ms
/delivery/cmp.php?&cdid=e84d132552193&h=https%3A%2F%2Fwww...	161 ms	145 ms	1.6 ms
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js	149 ms	82 ms	66 ms
www.googletagmanager.com/gtag/js?id=G-JE69ELWJLM	121 ms	80 ms	39 ms
cdn.consentmanager.net/delivery/js/cmp_final.min.js?t=2026-4-22	75 ms	38 ms	34 ms

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.

Category	Time Spent
Script Evaluation	2.3 s
Style & Layout	645 ms
Other	521 ms
Script Parsing & Compilation	288 ms
Parse HTML & CSS	256 ms
Rendering	68 ms
Garbage Collection	9.8 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 reason	Failure type
Pages with cache-control:no-store header cannot enter back/forward cache.	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.


v48n7 `div.grid-item > a.in-this-issue-imagelink > span.lrb-imageHolder > img.lazyload`
div.app-cta-griditem--thumb > a.imageLink > span.lrb-imageHolder > img.lazyload `div.app-cta-griditem--thumb > a.imageLink > span.lrb-imageHolder > img.lazyload`

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

●Optimize DOM size

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Avoids enormous network payloads Total size was 1,843 KiB

●User Timing marks and measures 26 user timings

●Avoid long main-thread tasks 12 long tasks found

●Network Requests

●Network Round Trip Times 40 ms

●Server Backend Latencies 380 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 110 ms

○INP breakdown

○Avoid non-composited animations

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

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Failing Elements
We use cookies to improve your experience on our website and to show you person… `div#cmpbox`

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.

○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

●Image elements have `[alt]` attributes

●Form elements have associated labels

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●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 are distinguishable without relying on color.

●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.

●`[lang]` attributes have a valid value

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Deprecated ARIA roles were not used

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○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

○Buttons have an accessible name

○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

○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.

○`<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.

○Identical links have the same purpose.

○Elements with visible text labels have matching accessible names.

○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.

Best Practices

General

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.

Source	Description
/api/4505029936742400/envelope/?sentry_version=7&sentry_k...	`Failed to load resource: the server responded with a status of 429 ()`

●Uses HTTPS

●Avoids deprecated APIs

●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

●Page has valid source maps

○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`