Who Must Comply with WCAG 2.1 AA in the UK?
Note: WCAG 2.2 was published in October 2023. PSBAR 2018 references WCAG 2.1 — WCAG 2.2 AA is a superset and is becoming the recommended standard. This guide covers WCAG 2.1 AA (the current UK legal requirement) with notes on WCAG 2.2 additions.
Organisation Type
Legal Basis
Requirement
UK Central Government websites
PSBAR 2018 (SI 2018/952)
WCAG 2.1 AA mandatory — Cabinet Office monitoring
UK Local Authority websites
PSBAR 2018
WCAG 2.1 AA mandatory
NHS and healthcare bodies
PSBAR 2018 + DTAC Domain 5
WCAG 2.1 AA mandatory
Educational institutions (FE/HE)
PSBAR 2018
WCAG 2.1 AA mandatory
Private sector (commercial)
Equality Act 2010
Reasonable adjustments — WCAG 2.1 AA best practice
FCA-regulated services
FCA Consumer Duty — Consumer Understanding
WCAG 2.1 AA strongly advised
NHS App Library applicants
DTAC Domain 5
WCAG 2.1 AA mandatory with evidence
The 4 WCAG Principles — UK Practical Summary
Perceivable: All information must be perceivable by all users. Key failures: images without alt text (NVDA screen reader cannot describe them), colour-only information (red/green traffic light — colour blind users cannot distinguish), insufficient colour contrast (< 4.5:1 ratio for normal text, < 3:1 for large text), and captions missing from videos.
Operable: All interface components must be operable. Key failures: keyboard traps (user cannot navigate past an element using keyboard only), no skip navigation link (NVDA users must tab through entire navigation on every page), focus indicator not visible (keyboard users cannot see where they are), and time limits without warnings.
Understandable: Information and UI operation must be understandable. Key failures: form errors not described in text (colour-only error indication), language not programmatically identified (screen readers cannot select the correct voice), confusing navigation (inconsistent patterns across pages), and required fields not labelled.
Robust: Content must be robust enough to be interpreted by assistive technologies. Key failures: invalid HTML (NVDA may misread content), ARIA labels not matching visible text (confusing for screen reader users), and components not accessible via ARIA roles.
Common WCAG 2.1 AA Failures in UK Software
| Failure | WCAG Criterion | How to Fix |
|---|---|---|
| Image without alt text | 1.1.1 Non-text Content | Add descriptive alt attribute; alt="" for decorative images |
| Colour contrast below 4.5:1 | 1.4.3 Contrast (Minimum) | Use contrast checker — adjust foreground/background colours |
| Form field without label | 1.3.1 Info and Relationships | Add <label> element with for= attribute matching input id= |
| No visible focus indicator | 2.4.7 Focus Visible | CSS :focus — never use outline: none without replacement |
| Keyboard trap in modal | 2.1.1 Keyboard | Trap focus within modal when open; release on close/Esc |
| Error identified by colour only | 1.4.1 Use of Colour | Add text description of error alongside colour indicator |
| Missing page language | 3.1.1 Language of Page | Add lang="en" to <html> element |
| No skip navigation | 2.4.1 Bypass Blocks | Add "Skip to main content" link as first focusable element |
Manual vs Automated WCAG Testing
ClickMasters WCAG 2.1 AA standard: automated Axe integration in CI/CD (every build), manual NVDA screen reader testing per sprint, keyboard-only navigation testing per sprint, colour contrast design review, and WCAG accessibility statement published on launch.
| Test Method | Issues Caught | Tools | ClickMasters Usage |
|---|---|---|---|
| Automated (Axe/Lighthouse) | ~30% of WCAG issues | Axe, Lighthouse, Pa11y | CI/CD on every build |
| Screen reader (NVDA/JAWS) | +40% additional issues | NVDA (free), JAWS (paid) | Sprint-level manual testing |
| Keyboard navigation manual | +15% additional issues | No tools needed | Sprint-level manual testing |
| Colour contrast manual | Overlaps with automated | Colour Contrast Analyser | Design review stage |
| Total with all methods | ~85–95% of WCAG issues | Combined approach | ClickMasters standard |