Skip to content
https://ncsc.gov.uk

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
85
GRADE
B
FIX
3
REVIEW
4
PASS
8
INFO
2

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

Mobile Desktop
55
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
91
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.

4.05 s

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

9.15 s

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

392 ms

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

0.000

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

4.60 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.

9.35 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
8 PASS 4 REVIEW 3 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (1.1 MiB of 1.1 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
JS Execution Cost
Action
2721ms total JS execution
FIX
2721ms total JS execution
Warning::
https://consent.cookiebot.com/41122ea9-38a1-4f2b-8...: 1121ms CPU time
Warning::
Unattributable: 608ms CPU time
Warning::
https://www.ncsc.gov.uk/: 315ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-P53...: 274ms CPU time
Info::
https://consent.cookiebot.com/uc.js: 138ms CPU time
Warning::
Third-party scripts: 2721ms (100% of total)

Main Thread Breakdown

Script Evaluation 39% Other 24% Parse HTML & CSS 14% Style & Layout 12% Script Parsing & Compilation 8%
ScriptTotalScriptingParse/CompileParty
https://consent.cookiebot.com/41122ea9-38a1-4f2b-8115-6804e417cddb/cc.js?renew=false&referer=www.ncsc.gov.uk&dnt=false&init=false1121ms556ms116ms3rd
Unattributable608ms65ms0ms3rd
https://www.ncsc.gov.uk/315ms24ms1ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-P53HXRL7274ms200ms70ms3rd
https://consent.cookiebot.com/uc.js138ms117ms15ms3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-site-BQlwULPI.js116ms68ms0ms3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//gsap-core-DxSJLJiy.js95ms18ms0ms3rd
https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da177152312451654ms35ms5ms3rd
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
Page Weight Budget
1.1 MB transferred, 52 requests
REVIEW
1.1 MB transferred, 52 requests
Info::
Page weighs 2.6 MB (1.1 MB transferred)
Warning::
JavaScript is 810 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 810 KB
Info::
52 HTTP requests
Info::
Estimated 0.22 g CO2 per page load
1.1 MB / 2.4 MB budget
1.1 MB transferred
52 requests
0.22 g CO2 per page load
JavaScript 809.8 KiB 74%
Images 205.0 KiB 19%
Fonts 32.1 KiB 3%
HTML 25.9 KiB 2%
CSS 14.8 KiB 1%
Other 6.2 KiB 1%
Other 1.1 KiB 0%
0 2.4 MB 4.9 MB
Under budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

B
Image Optimization
9 images, 0 KB saveable
REVIEW
9 images, 0 KB saveable
Info::
All images are well-optimized
9 images 205 KB
0 oversized -0 KB
7 legacy format
0 missing dimensions CLS risk
B
JS Bundles
29 scripts, 150 KB unused
REVIEW
29 scripts, 150 KB unused
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-P53...: 66 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://consent.cookiebot.com/41122ea9-38a1-4f2b-8...: 60 KB unused (11%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://consent.cookiebot.com/uc.js: 23 KB unused (64%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 150 KB
150 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtm.js?id=GTM-P53HXRL7137 KB66 KB (49%)✓3rd
https://consent.cookiebot.com/41122ea9-38a1-4f2b-8115-6804e417cddb/cc.js?renew=false&referer=www.ncsc.gov.uk&dnt=false&init=false545 KB60 KB (11%)✓3rd
https://consent.cookiebot.com/uc.js36 KB23 KB (64%)✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//cookiebot-CMChdO_I.js1 KB—✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist/_menu-multistep-DRAno3XV.js3 KB—✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.js?tdl6951 KB—✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-site-BQlwULPI.js4 KB—✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-BS2ZtZlT.js1 KB—✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-DbeyCpiN.js1 KB—✓3rd
https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-CzKEB6Cx.js1 KB—✓3rd

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

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

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

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

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
4 fonts (32 KB)
PASS
4 fonts (32 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

32 KB total

Render-blocking

0

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s 9.0 s FCP 4.0 s LCP 9.1 shttps://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-regular-latin-DkxLoFEk.woff2poppins-regular-latin-D... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-regular-latin-DkxLoFEk.woff2 — 8.1 KiB — 36 ms — font-display: swaphttps://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-semibold-latin-D_ZEWkNb.woff2poppins-semibold-latin-... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-semibold-latin-D_ZEWkNb.woff2 — 7.9 KiB — 34 ms — font-display: swaphttps://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-bold-latin-BFfy0D5Z.woff2poppins-bold-latin-BFfy... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-bold-latin-BFfy0D5Z.woff2 — 8.0 KiB — 32 ms — font-display: swaphttps://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-medium-latin-2Mu8yu1G.woff2poppins-medium-latin-2M... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-medium-latin-2Mu8yu1G.woff2 — 8.1 KiB — 30 ms — font-display: swap
poppins-regular-latin-D... woff2 swap
Size 8 KB
Load time 36 ms
Start 129 ms
Risk FOUT — text flashes from fallback to web font
poppins-semibold-latin-... woff2 swap
Size 8 KB
Load time 34 ms
Start 129 ms
Risk FOUT — text flashes from fallback to web font
poppins-bold-latin-BFfy... woff2 swap
Size 8 KB
Load time 32 ms
Start 283 ms
Risk FOUT — text flashes from fallback to web font
poppins-medium-latin-2M... woff2 swap
Size 8 KB
Load time 30 ms
Start 283 ms
Risk FOUT — text flashes from fallback to web font
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)
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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
Page uses 3 resource hint(s)

Current Resource Hints

preconnect
1
preload
2
dns-prefetch
—
prefetch
—

3 resource hints configured

A
Page Weight Inventory
52 resources · 1.1 MB · 150 KB savings available
PASS
52 resources · 1.1 MB · 150 KB savings available
Warning::
Page weight 71 KB over 1MB target
Got: 1.1 MB Expected: ≤ 1 MB
Info::
~150 KB of savings available
Warning::
51 third-party resources (100% of weight)
Info::
1 resources over 200KB
52 resources · 1.1 MiB · 51 third-party 70.9 KiB over 1MB target
JavaScript 74% · 809.8 KiB
Image 19% · 210.7 KiB
Font 3% · 32.1 KiB
Document 2% · 25.9 KiB
CSS 1% · 14.8 KiB
Other 0% · 1.6 KiB

~149.6 KiB of savings available

Remove unused JavaScript: 149.6 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
Network Waterfall
52 requests over 2306ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s 9.0 s FCP 4.0 s LCP 9.1 shttps://ncsc.gov.uk// https://ncsc.gov.uk/ — 301 — 238 B — 18 ms — h2http://www.ncsc.gov.uk/www.ncsc.gov.uk/ http://www.ncsc.gov.uk/ — 307 — 0 B — 1 ms — http/1.1https://www.ncsc.gov.uk/www.ncsc.gov.uk/ https://www.ncsc.gov.uk/ — 200 — 25.2 KiB — 92 ms — h3https://www.ncsc.gov.uk/cdn-cgi/speculationwww.ncsc.gov.uk/cdn-cgi/speculation https://www.ncsc.gov.uk/cdn-cgi/speculation — 200 — 287 B — 6 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-regular-latin-DkxLoFEk.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-regular-latin-DkxLoFEk.woff2 — 200 — 8.1 KiB — 36 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-semibold-latin-D_ZEWkNb.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-semibold-latin-D_ZEWkNb.woff2 — 200 — 7.9 KiB — 34 ms — h3https://consent.cookiebot.com/uc.jsconsent.cookiebot.com/uc.js https://consent.cookiebot.com/uc.js — 200 — 35.7 KiB — 68 ms — h2https://www.ncsc.gov.uk/sites/default/files/css/css_HZUYmcBk-xep5jxvzjmxAJ8YfKVBvapM2l5oADQ552s.css?delta=0&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZawwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/css/css_HZUYmcBk-xep5jxvzjmxAJ8YfKVBvapM2l5oADQ552s.css?delta=0&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZaw — 200 — 598 B — 42 ms — h3https://www.ncsc.gov.uk/sites/default/files/css/css_K_97nM_iJvTIWk8DJA9yXRTPh-ySzbAqwAty6l0jhp4.css?delta=1&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZawwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/css/css_K_97nM_iJvTIWk8DJA9yXRTPh-ySzbAqwAty6l0jhp4.css?delta=1&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZaw — 200 — 14.2 KiB — 40 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/ncsc-logo-CarDIzNF.svgwww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/ncsc-logo-CarDIzNF.svg — 200 — 19.4 KiB — 46 ms — h3https://www.ncsc.gov.uk/sites/default/files/js/js_7TxMCm84GbtH3OsolONoTzH4Od6wkRdfUH0whIVMipA.js?scope=footer&delta=0&language=en&theme=ennerdale&include=eJzLScxOLdZPz8lPSszRLU4uyiwoKQYAUWkH5gwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/js/js_7TxMCm84GbtH3OsolONoTzH4Od6wkRdfUH0whIVMipA.js?scope=footer&delta=0&language=en&theme=ennerdale&include=eJzLScxOLdZPz8lPSszRLU4uyiwoKQYAUWkH5g — 200 — 2.2 KiB — 35 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.js?tdl695www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.js?tdl695 — 200 — 1.1 KiB — 36 ms — h3https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 30 ms — h2https://consentcdn.cookiebot.com/consentconfig/41122ea9-38a1-4f2b-8115-6804e417cddb/settings.jsonconsentcdn.cookiebot.com/consentcon... https://consentcdn.cookiebot.com/consentconfig/41122ea9-38a1-4f2b-8115-6804e417cddb/settings.json — 200 — 954 B — 17 ms — h2https://consent.cookiebot.com/41122ea9-38a1-4f2b-8115-6804e417cddb/cc.js?renew=false&referer=www.ncsc.gov.uk&dnt=false&init=falseconsent.cookiebot.com/41122ea9-38a1... https://consent.cookiebot.com/41122ea9-38a1-4f2b-8115-6804e417cddb/cc.js?renew=false&referer=www.ncsc.gov.uk&dnt=false&init=false — 200 — 544.8 KiB — 578 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-P53HXRL7www.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-P53HXRL7 — 200 — 136.7 KiB — 254 ms — h2https://www.ncsc.gov.uk/sites/default/files/images/ss-rr-1.svgwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/images/ss-rr-1.svg — 200 — 18.4 KiB — 74 ms — h3https://www.ncsc.gov.uk/sites/default/files/images/rr-ml.svgwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/images/rr-ml.svg — 200 — 56.3 KiB — 86 ms — h3https://www.ncsc.gov.uk/sites/default/files/images/if-rr.svgwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/images/if-rr.svg — 200 — 30.3 KiB — 85 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-bold-latin-BFfy0D5Z.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-bold-latin-BFfy0D5Z.woff2 — 200 — 8.0 KiB — 32 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-medium-latin-2Mu8yu1G.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-medium-latin-2Mu8yu1G.woff2 — 200 — 8.1 KiB — 30 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-site-BQlwULPI.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-site-BQlwULPI.js — 200 — 4.4 KiB — 30 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-BS2ZtZlT.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-BS2ZtZlT.js — 200 — 651 B — 32 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-DbeyCpiN.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-DbeyCpiN.js — 200 — 516 B — 67 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-CzKEB6Cx.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-CzKEB6Cx.js — 200 — 534 B — 53 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-qO1EBtTd.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-qO1EBtTd.js — 200 — 540 B — 57 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//external-links-DecikCFs.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//external-links-DecikCFs.js — 200 — 864 B — 64 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//a11y-tabbing-DXUkXkdA.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//a11y-tabbing-DXUkXkdA.js — 200 — 419 B — 68 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//analytics-DUzM1UzB.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//analytics-DUzM1UzB.js — 200 — 977 B — 72 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//cookiebot-CMChdO_I.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//cookiebot-CMChdO_I.js — 200 — 605 B — 58 ms — h3
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s 6.0 s 7.0 s 8.0 s 9.0 s FCP 4.0 s LCP 9.1 shttps://ncsc.gov.uk// https://ncsc.gov.uk/ — 301 — 238 B — 18 ms — h2http://www.ncsc.gov.uk/www.ncsc.gov.uk/ http://www.ncsc.gov.uk/ — 307 — 0 B — 1 ms — http/1.1https://www.ncsc.gov.uk/www.ncsc.gov.uk/ https://www.ncsc.gov.uk/ — 200 — 25.2 KiB — 92 ms — h3https://www.ncsc.gov.uk/cdn-cgi/speculationwww.ncsc.gov.uk/cdn-cgi/speculation https://www.ncsc.gov.uk/cdn-cgi/speculation — 200 — 287 B — 6 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-regular-latin-DkxLoFEk.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-regular-latin-DkxLoFEk.woff2 — 200 — 8.1 KiB — 36 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-semibold-latin-D_ZEWkNb.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-semibold-latin-D_ZEWkNb.woff2 — 200 — 7.9 KiB — 34 ms — h3https://consent.cookiebot.com/uc.jsconsent.cookiebot.com/uc.js https://consent.cookiebot.com/uc.js — 200 — 35.7 KiB — 68 ms — h2https://www.ncsc.gov.uk/sites/default/files/css/css_HZUYmcBk-xep5jxvzjmxAJ8YfKVBvapM2l5oADQ552s.css?delta=0&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZawwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/css/css_HZUYmcBk-xep5jxvzjmxAJ8YfKVBvapM2l5oADQ552s.css?delta=0&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZaw — 200 — 598 B — 42 ms — h3https://www.ncsc.gov.uk/sites/default/files/css/css_K_97nM_iJvTIWk8DJA9yXRTPh-ySzbAqwAty6l0jhp4.css?delta=1&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZawwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/css/css_K_97nM_iJvTIWk8DJA9yXRTPh-ySzbAqwAty6l0jhp4.css?delta=1&language=en&theme=ennerdale&include=eJxLyy_KjS_N1E8pKi1IzNFLg3D1iksyk7Mr44tTk_PzUhKLKuPzEst0chKzU4v103PykxJzdItLKnMy89IBO1YZaw — 200 — 14.2 KiB — 40 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/ncsc-logo-CarDIzNF.svgwww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/ncsc-logo-CarDIzNF.svg — 200 — 19.4 KiB — 46 ms — h3https://www.ncsc.gov.uk/sites/default/files/js/js_7TxMCm84GbtH3OsolONoTzH4Od6wkRdfUH0whIVMipA.js?scope=footer&delta=0&language=en&theme=ennerdale&include=eJzLScxOLdZPz8lPSszRLU4uyiwoKQYAUWkH5gwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/js/js_7TxMCm84GbtH3OsolONoTzH4Od6wkRdfUH0whIVMipA.js?scope=footer&delta=0&language=en&theme=ennerdale&include=eJzLScxOLdZPz8lPSszRLU4uyiwoKQYAUWkH5g — 200 — 2.2 KiB — 35 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.js?tdl695www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.js?tdl695 — 200 — 1.1 KiB — 36 ms — h3https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 30 ms — h2https://consentcdn.cookiebot.com/consentconfig/41122ea9-38a1-4f2b-8115-6804e417cddb/settings.jsonconsentcdn.cookiebot.com/consentcon... https://consentcdn.cookiebot.com/consentconfig/41122ea9-38a1-4f2b-8115-6804e417cddb/settings.json — 200 — 954 B — 17 ms — h2https://consent.cookiebot.com/41122ea9-38a1-4f2b-8115-6804e417cddb/cc.js?renew=false&referer=www.ncsc.gov.uk&dnt=false&init=falseconsent.cookiebot.com/41122ea9-38a1... https://consent.cookiebot.com/41122ea9-38a1-4f2b-8115-6804e417cddb/cc.js?renew=false&referer=www.ncsc.gov.uk&dnt=false&init=false — 200 — 544.8 KiB — 578 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-P53HXRL7www.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-P53HXRL7 — 200 — 136.7 KiB — 254 ms — h2https://www.ncsc.gov.uk/sites/default/files/images/ss-rr-1.svgwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/images/ss-rr-1.svg — 200 — 18.4 KiB — 74 ms — h3https://www.ncsc.gov.uk/sites/default/files/images/rr-ml.svgwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/images/rr-ml.svg — 200 — 56.3 KiB — 86 ms — h3https://www.ncsc.gov.uk/sites/default/files/images/if-rr.svgwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/images/if-rr.svg — 200 — 30.3 KiB — 85 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-bold-latin-BFfy0D5Z.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-bold-latin-BFfy0D5Z.woff2 — 200 — 8.0 KiB — 32 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-medium-latin-2Mu8yu1G.woff2www.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/poppins-medium-latin-2Mu8yu1G.woff2 — 200 — 8.1 KiB — 30 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-site-BQlwULPI.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-site-BQlwULPI.js — 200 — 4.4 KiB — 30 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-BS2ZtZlT.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-BS2ZtZlT.js — 200 — 651 B — 32 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-DbeyCpiN.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-DbeyCpiN.js — 200 — 516 B — 67 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-CzKEB6Cx.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-CzKEB6Cx.js — 200 — 534 B — 53 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-qO1EBtTd.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-qO1EBtTd.js — 200 — 540 B — 57 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//external-links-DecikCFs.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//external-links-DecikCFs.js — 200 — 864 B — 64 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//a11y-tabbing-DXUkXkdA.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//a11y-tabbing-DXUkXkdA.js — 200 — 419 B — 68 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//analytics-DUzM1UzB.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//analytics-DUzM1UzB.js — 200 — 977 B — 72 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//cookiebot-CMChdO_I.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//cookiebot-CMChdO_I.js — 200 — 605 B — 58 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//main-CFqqOeQV.js — 200 — 1.1 KiB — 52 ms — h3https://consentcdn.cookiebot.com/sdk/bc-v4.min.htmlconsentcdn.cookiebot.com/sdk/bc-v4.... https://consentcdn.cookiebot.com/sdk/bc-v4.min.html — 200 — 810 B — 38 ms — h2https://www.ncsc.gov.uk/themes/custom/lakes/dist/_menu-multistep-DRAno3XV.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/_menu-multistep-DRAno3XV.js — 200 — 2.8 KiB — 42 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/breakpoints.config-BzU5xyI3.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/breakpoints.config-BzU5xyI3.js — 200 — 456 B — 41 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/dropdown-toggle-Cjb_x3mc.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/dropdown-toggle-Cjb_x3mc.js — 200 — 2.1 KiB — 41 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/index-B6oLHIQH.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/index-B6oLHIQH.js — 200 — 8.0 KiB — 55 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/gsap-core-DxSJLJiy.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/gsap-core-DxSJLJiy.js — 200 — 19.8 KiB — 55 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist/search-dropdown-CSa6OYjo.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist/search-dropdown-CSa6OYjo.js — 200 — 635 B — 35 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//teaser-label-expiry-DVIz5lZK.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//teaser-label-expiry-DVIz5lZK.js — 200 — 504 B — 54 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//_menu-multistep-DRAno3XV.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//_menu-multistep-DRAno3XV.js — 200 — 2.8 KiB — 42 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//search-dropdown-CSa6OYjo.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//search-dropdown-CSa6OYjo.js — 200 — 635 B — 48 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//breakpoints.config-BzU5xyI3.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//breakpoints.config-BzU5xyI3.js — 200 — 456 B — 26 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//dropdown-toggle-Cjb_x3mc.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//dropdown-toggle-Cjb_x3mc.js — 200 — 2.1 KiB — 29 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-B6oLHIQH.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//index-B6oLHIQH.js — 200 — 8.0 KiB — 47 ms — h3https://www.ncsc.gov.uk/themes/custom/lakes/dist//gsap-core-DxSJLJiy.jswww.ncsc.gov.uk/themes/custom/lakes... https://www.ncsc.gov.uk/themes/custom/lakes/dist//gsap-core-DxSJLJiy.js — 200 — 19.8 KiB — 40 ms — h3data:image/jpeg;base64,/9j/4gxYSUNDX1BST0ZJTEUAAQEAAAxITGlubwIQAABtbnRyUkdCIFhZWiAHzgACAAkABgAxAABh…data:image/jpeg;base64,/9j/4gxYSUND... data:image/jpeg;base64,/9j/4gxYSUNDX1BST0ZJTEUAAQEAAAxITGlubwIQAABtbnRyUkdCIFhZWiAHzgACAAkABgAxAABh… — 200 — 0 B — 8 ms — datadata:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAASCAYAAABWzo5XAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAA…data:image/png;base64,iVBORw0KGgoAA... data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAASCAYAAABWzo5XAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAA… — 200 — 0 B — 0 ms — datahttps://www.ncsc.gov.uk/cdn-cgi/rum?www.ncsc.gov.uk/cdn-cgi/rum? https://www.ncsc.gov.uk/cdn-cgi/rum? — 204 — 197 B — 11 ms — h3https://www.ncsc.gov.uk/themes/custom/ennerdale/favicons/favicon.icowww.ncsc.gov.uk/themes/custom/enner... https://www.ncsc.gov.uk/themes/custom/ennerdale/favicons/favicon.ico — 200 — 5.7 KiB — 31 ms — h3https://www.ncsc.gov.uk/sites/default/files/styles/16_9_media_sm/public/2026-04/Glasgow-skyline.jpg?h=119335f7&itok=zrQKV9JGwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/styles/16_9_media_sm/public/2026-04/Glasgow-skyline.jpg?h=119335f7&itok=zrQKV9JG — 200 — 35.2 KiB — 412 ms — h3https://www.ncsc.gov.uk/sites/default/files/styles/1_1_media_xs/public/2026-04/cross%20domain%20blog.jpg?h=119335f7&itok=n1kRcUfcwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/styles/1_1_media_xs/public/2026-04/cross%20domain%20blog.jpg?h=119335f7&itok=n1kRcUfc — 200 — 33.1 KiB — 436 ms — h3https://www.ncsc.gov.uk/sites/default/files/styles/1_1_media_xs/public/2026-04/severe-cyber-threat-blog.jpg?h=eca34813&itok=hGnSVrIBwww.ncsc.gov.uk/sites/default/files... https://www.ncsc.gov.uk/sites/default/files/styles/1_1_media_xs/public/2026-04/severe-cyber-threat-blog.jpg?h=eca34813&itok=hGnSVrIB — 200 — 12.4 KiB — 441 ms — h3
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 2721ms · 777KB · £28/mo
consent.cookiebot.com
Other
Costly
Execution 1121ms
Transfer 545 KB
Unused 11%
Monthly Cost £12/mo
Unattributable
Other
Costly
Execution 608ms
Transfer 0 KB
Monthly Cost £6/mo
www.ncsc.gov.uk
Other
Costly
Execution 315ms
Transfer 25 KB
Monthly Cost £3/mo
Google Tag Manager
Tag Manager
Costly
Execution 274ms
Transfer 137 KB
Unused 49%
Monthly Cost £3/mo
consent.cookiebot.com
Other
Optional
Execution 138ms
Transfer 36 KB
Unused 64%
Monthly Cost £1/mo
www.ncsc.gov.uk
Other
Optional
Execution 116ms
Transfer 4 KB
Monthly Cost £1/mo
www.ncsc.gov.uk
Other
Optional
Execution 95ms
Transfer 20 KB
Monthly Cost £1/mo
static.cloudflareinsights.com
Other
Optional
Execution 54ms
Transfer 11 KB
Monthly Cost £1/mo

These scripts may cost more than they're worth

  • consent.cookiebot.com adds 1121ms and costs ~£12/month
  • Unattributable adds 608ms and costs ~£6/month
  • www.ncsc.gov.uk adds 315ms and costs ~£3/month
  • Google Tag Manager adds 274ms and costs ~£3/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

consent.cookiebot.com takes 1121ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

Unattributable takes 608ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.ncsc.gov.uk takes 315ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

Google Tag Manager takes 274ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

64% of consent.cookiebot.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

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.

Send Feedback