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https://ico.org.uk

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
93
GRADE
A
FIX
1
REVIEW
3
PASS
11
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
75
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

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

1.06 s

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

2.33 s

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

92 ms

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

0.651

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

1.75 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.

2.34 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
17
11 PASS 3 REVIEW 1 FIX
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

B
Third-Party Impact
46% third-party, 0 ms blocking
REVIEW
46% third-party, 0 ms blocking
Info::
Third-party code accounts for 46% of page weight (93.5 KiB of 201.2 KiB)
Info::
Third-party blocking time is low (0 ms)
54%
46%
First-party Third-party
B
Image Optimization
18 images, 0 KB saveable
REVIEW
18 images, 0 KB saveable
Info::
All images are well-optimized
18 images 43 KB
0 oversized -0 KB
8 legacy format
0 missing dimensions CLS risk
B
JS Execution Cost
737ms total JS execution
REVIEW
737ms total JS execution
Info::
https://cc.cdn.civiccomputing.com/9/cookieControl-...: 194ms CPU time
Info::
Unattributable: 191ms CPU time
Info::
https://ico.org.uk/: 190ms CPU time
Info::
https://ico.org.uk/js/index.js?v=lzVtN7n9HO9sYcg02...: 162ms CPU time
Warning::
Third-party scripts: 385ms (52% of total)

Main Thread Breakdown

Script Evaluation 33% Other 32% Style & Layout 21% Script Parsing & Compilation 5% Rendering 5% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://cc.cdn.civiccomputing.com/9/cookieControl-9.9.min.js194ms158ms35ms3rd
Unattributable191ms6ms0ms3rd
https://ico.org.uk/190ms11ms0ms1st
https://ico.org.uk/js/index.js?v=lzVtN7n9HO9sYcg02GpHp-tXu9pXXxBMG3QvE9_Dloc162ms72ms4ms1st
A+
Page Weight Budget
201 KB transferred, 25 requests
PASS
201 KB transferred, 25 requests
Info::
Page weighs 605 KB (201 KB transferred)
Info::
25 HTTP requests
Info::
Estimated 0.04 g CO2 per page load
201 KB / 2.4 MB budget
201 KB transferred
25 requests
0.04 g CO2 per page load
JavaScript 105.1 KiB 52%
Images 42.8 KiB 21%
CSS 25.3 KiB 13%
Fonts 17.2 KiB 9%
HTML 9.3 KiB 5%
Other 935 B 0%
Other 607 B 0%
0 2.4 MB 4.9 MB
Under budget
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
1 fonts (17 KB)
PASS
1 fonts (17 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

17 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.1 s LCP 2.3 shttps://ico.org.uk/fonts/icons-default.ttf?w9uwepicons-default.ttf https://ico.org.uk/fonts/icons-default.ttf?w9uwep — 17.2 KiB — 38 ms — font-display: swap
icons-default.ttf ttf swap
Size 17 KB
Load time 38 ms
Start 169 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~5 KB and ~10 ms

A+
JS Bundles
2 scripts, 42 KB unused
PASS
2 scripts, 42 KB unused
Warning::
https://cc.cdn.civiccomputing.com/9/cookieControl-...: 42 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 42 KB
42 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cc.cdn.civiccomputing.com/9/cookieControl-9.9.min.js93 KB42 KB (46%)✓3rd
https://ico.org.uk/js/index.js?v=lzVtN7n9HO9sYcg02GpHp-tXu9pXXxBMG3QvE9_Dloc12 KB—✓1st

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A
Page Weight Inventory
25 resources · 201 KB · 42 KB savings available
PASS
25 resources · 201 KB · 42 KB savings available
Info::
Within 1MB page-weight target
Got: 201 KB
Warning::
2 third-party resources (46% of weight)
25 resources · 201.2 KiB · 2 third-party Within 1MB page-weight target
JavaScript 52% · 105.1 KiB
Image 22% · 43.7 KiB
CSS 13% · 25.3 KiB
Font 9% · 17.2 KiB
Document 5% · 9.3 KiB
Other 0% · 607 B

~42.4 KiB of savings available

Remove unused JavaScript: 42.4 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
25 requests over 510ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.1 s LCP 2.3 shttps://ico.org.uk// https://ico.org.uk/ — 200 — 9.3 KiB — 94 ms — h2https://ico.org.uk/css/site.css?v=BwOVC9vVV6268LypYZd3tkCsM63Es5d1IY4UaqUcee8/css/site.css?v=BwOVC9vVV6268LypYZd... https://ico.org.uk/css/site.css?v=BwOVC9vVV6268LypYZd3tkCsM63Es5d1IY4UaqUcee8 — 200 — 25.3 KiB — 36 ms — h2https://ico.org.uk/media2/qkcg1rdf/logo-small.svg?width=80&height=32&v=1db03b868bf60c0/media2/qkcg1rdf/logo-small.svg?wid... https://ico.org.uk/media2/qkcg1rdf/logo-small.svg?width=80&height=32&v=1db03b868bf60c0 — 200 — 908 B — 35 ms — h2https://ico.org.uk/media2/myukqaa2/ico-header-logo.svg?width=160&height=96&v=1db03b866f17e90/media2/myukqaa2/ico-header-logo.sv... https://ico.org.uk/media2/myukqaa2/ico-header-logo.svg?width=160&height=96&v=1db03b866f17e90 — 200 — 2.7 KiB — 33 ms — h2https://cc.cdn.civiccomputing.com/9/cookieControl-9.9.min.jscc.cdn.civiccomputing.com/9/cookieC... https://cc.cdn.civiccomputing.com/9/cookieControl-9.9.min.js — 200 — 92.9 KiB — 166 ms — h3https://ico.org.uk/js/index.js?v=lzVtN7n9HO9sYcg02GpHp-tXu9pXXxBMG3QvE9_Dloc/js/index.js?v=lzVtN7n9HO9sYcg02GpH... https://ico.org.uk/js/index.js?v=lzVtN7n9HO9sYcg02GpHp-tXu9pXXxBMG3QvE9_Dloc — 200 — 12.1 KiB — 31 ms — h2https://ico.org.uk/media2/3e3molj2/x-logo-1.svg?width=24&height=24&v=1db7d782a8d9170/media2/3e3molj2/x-logo-1.svg?width... https://ico.org.uk/media2/3e3molj2/x-logo-1.svg?width=24&height=24&v=1db7d782a8d9170 — 200 — 487 B — 32 ms — h2https://ico.org.uk/media2/z3vdkkxj/youtube.svg?width=24&height=24&v=1db042ab32beee0/media2/z3vdkkxj/youtube.svg?width=... https://ico.org.uk/media2/z3vdkkxj/youtube.svg?width=24&height=24&v=1db042ab32beee0 — 200 — 772 B — 36 ms — h2https://ico.org.uk/media2/cgdpvn4n/linkedin.svg?width=24&height=24&v=1db042ab2dda7d0/media2/cgdpvn4n/linkedin.svg?width... https://ico.org.uk/media2/cgdpvn4n/linkedin.svg?width=24&height=24&v=1db042ab2dda7d0 — 200 — 752 B — 37 ms — h2https://ico.org.uk/media2/g2nhkyjv/facebook.svg?width=24&height=24&v=1db03b86b4b62d0/media2/g2nhkyjv/facebook.svg?width... https://ico.org.uk/media2/g2nhkyjv/facebook.svg?width=24&height=24&v=1db03b86b4b62d0 — 200 — 623 B — 29 ms — h2https://ico.org.uk/media2/thzeryz5/envelope.svg?width=24&height=24&v=1db03b86a1d4310/media2/thzeryz5/envelope.svg?width... https://ico.org.uk/media2/thzeryz5/envelope.svg?width=24&height=24&v=1db03b86a1d4310 — 200 — 955 B — 34 ms — h2https://ico.org.uk/media2/r34b3hma/ogl.png?width=40&height=16&v=1dc6f3b2af11af0/media2/r34b3hma/ogl.png?width=40&h... https://ico.org.uk/media2/r34b3hma/ogl.png?width=40&height=16&v=1dc6f3b2af11af0 — 200 — 725 B — 32 ms — h2https://ico.org.uk/fonts/icons-default.ttf?w9uwep/fonts/icons-default.ttf?w9uwep https://ico.org.uk/fonts/icons-default.ttf?w9uwep — 200 — 17.2 KiB — 38 ms — h2https://apikeys.civiccomputing.com/c/v?d=ico.org.uk&p=CookieControl%20Single-Site&v=9&k=dbf86e044f3ab8c4df852af5c7c6ceb2dd7678dd&format=jsonapikeys.civiccomputing.com/c/v?d=ic... https://apikeys.civiccomputing.com/c/v?d=ico.org.uk&p=CookieControl%20Single-Site&v=9&k=dbf86e044f3ab8c4df852af5c7c6ceb2dd7678dd&format=json — 200 — 607 B — 160 ms — h3https://ico.org.uk/media2/jekcohbe/sotp-website-twitter-card-d-1.jpg?width=510&height=400&v=1dcc81525613bf0&format=webp/media2/jekcohbe/sotp-website-twitt... https://ico.org.uk/media2/jekcohbe/sotp-website-twitter-card-d-1.jpg?width=510&height=400&v=1dcc81525613bf0&format=webp — 200 — 6.5 KiB — 29 ms — h2https://ico.org.uk/media2/rmzfonwb/impact-homepage-link-graphic.png?width=100&height=100&v=1dc8af3780f58f0&format=webp/media2/rmzfonwb/impact-homepage-li... https://ico.org.uk/media2/rmzfonwb/impact-homepage-link-graphic.png?width=100&height=100&v=1dc8af3780f58f0&format=webp — 200 — 3.6 KiB — 29 ms — h2https://ico.org.uk/media2/i15jzjvi/sotp-homepage-link-graphic-b-0904.png?width=100&height=100&v=1dcc81524933d90&format=webp/media2/i15jzjvi/sotp-homepage-link... https://ico.org.uk/media2/i15jzjvi/sotp-homepage-link-graphic-b-0904.png?width=100&height=100&v=1dcc81524933d90&format=webp — 200 — 4.4 KiB — 30 ms — h2https://ico.org.uk/media2/migrated/2259011/ydm-access-180x180.gif?width=96&height=96&v=1db03b916558ca0&format=webp/media2/migrated/2259011/ydm-access... https://ico.org.uk/media2/migrated/2259011/ydm-access-180x180.gif?width=96&height=96&v=1db03b916558ca0&format=webp — 200 — 3.3 KiB — 34 ms — h2https://ico.org.uk/media2/migrated/2259127/ydm-official-information-180x180.gif?width=96&height=96&v=1db03b917e7ec70&format=webp/media2/migrated/2259127/ydm-offici... https://ico.org.uk/media2/migrated/2259127/ydm-official-information-180x180.gif?width=96&height=96&v=1db03b917e7ec70&format=webp — 200 — 3.2 KiB — 31 ms — h2https://ico.org.uk/media2/migrated/2259031/ydm-concern-180x180.gif?width=96&height=96&v=1db03b91a037970&format=webp/media2/migrated/2259031/ydm-concer... https://ico.org.uk/media2/migrated/2259031/ydm-concern-180x180.gif?width=96&height=96&v=1db03b91a037970&format=webp — 200 — 4.0 KiB — 38 ms — h2https://ico.org.uk/media2/migrated/4030917/ydm-social-media-180x180.png?width=96&height=96&v=1db03b9208ce7e0&format=webp/media2/migrated/4030917/ydm-social... https://ico.org.uk/media2/migrated/4030917/ydm-social-media-180x180.png?width=96&height=96&v=1db03b9208ce7e0&format=webp — 200 — 2.0 KiB — 32 ms — h2https://ico.org.uk/media2/xnlb3iea/data-use-and-access-180x180.jpg?width=96&height=96&v=1dbe1c28051a160&format=webp/media2/xnlb3iea/data-use-and-acces... https://ico.org.uk/media2/xnlb3iea/data-use-and-access-180x180.jpg?width=96&height=96&v=1dbe1c28051a160&format=webp — 200 — 2.3 KiB — 39 ms — h2https://ico.org.uk/media2/migrated/1316/laptop-180x180.jpg?width=96&height=96&v=1db34ae06838cc0&format=webp/media2/migrated/1316/laptop-180x18... https://ico.org.uk/media2/migrated/1316/laptop-180x180.jpg?width=96&height=96&v=1db34ae06838cc0&format=webp — 200 — 2.7 KiB — 36 ms — h2https://ico.org.uk/media2/migrated/1340/publication-180x180.jpg?width=96&height=96&v=1db34ae08f947b0&format=webp/media2/migrated/1340/publication-1... https://ico.org.uk/media2/migrated/1340/publication-180x180.jpg?width=96&height=96&v=1db34ae08f947b0&format=webp — 200 — 2.9 KiB — 34 ms — h2https://ico.org.uk/media2/lhphq55z/favicon.ico/media2/lhphq55z/favicon.ico https://ico.org.uk/media2/lhphq55z/favicon.ico — 200 — 935 B — 30 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
52% of JavaScript execution is third-party
First-party Third-party 385ms · 93KB · £4/mo
cc.cdn.civiccomputing.com
Other
Optional
Execution 194ms
Transfer 93 KB
Unused 46%
Monthly Cost £2/mo
Unattributable
Other
Optional
Execution 191ms
Transfer 0 KB
Monthly Cost £2/mo

52% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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