WCAG (Web Content Accessibility Guidelines)
International accessibility standards for web and mobile content; WCAG 2.1 AA is the default UK public sector requirement.
Definition
WCAG (Web Content Accessibility Guidelines) are international accessibility standards for web and mobile content published by the World Wide Web Consortium (W3C). The current widely-adopted version is WCAG 2.1 with three conformance levels (A, AA, AAA). WCAG 2.2 was published in 2023 with additional success criteria but adoption is still rolling out. UK public sector digital services must meet WCAG 2.1 AA under the Public Sector Bodies Accessibility Regulations 2018.
How it works in practice
WCAG is structured around four principles: perceivable (information presented in ways users can perceive, including alternative text, captions, sufficient contrast), operable (interface components users can operate, including keyboard navigation, no seizure-inducing content), understandable (information and operation predictable, including consistent behaviour, error identification, plain language), and robust (compatibility with assistive technology including screen readers and switch devices). Each principle has success criteria at A, AA, and AAA conformance levels. AA conformance requires meeting all A and AA criteria. Typical WCAG audit combines automated tools (axe-core, Wave, Lighthouse accessibility audits) with manual testing using assistive technology (screen readers like JAWS or NVDA, keyboard-only navigation, voice control software). The audit produces a conformance report identifying issues at each WCAG criterion. Remediation prioritises issues by impact and frequency: critical issues blocking core user journeys before nice-to-haves on edge cases. For suppliers building public sector digital services WCAG conformance evidence is increasingly a contract obligation tracked through service-acceptance criteria. The KimonBids accessibility module tracks WCAG audit dates and surfaces re-audit reminders.
Common questions
What is the difference between WCAG 2.1 and WCAG 2.2?
WCAG 2.2 adds nine new success criteria addressing modern interaction patterns including focus appearance, dragging movements, target size, and form fields. The new criteria are mostly at AA level. UK public sector regulations currently reference WCAG 2.1; over time the regulations will update to WCAG 2.2 or successor. Suppliers should design for the higher standard where practical.
Can WCAG conformance be tested automatically?
Partially. Automated tools can detect approximately 30-40 percent of WCAG issues (missing alternative text, contrast issues, programmatic structure problems). The remaining 60-70 percent require manual testing with assistive technology. Full WCAG audit requires both automated scanning and manual testing.
How does WCAG relate to the Equality Act?
Inaccessible digital services can attract Equality Act discrimination claims, particularly where they disadvantage users with disabilities. WCAG conformance substantially reduces this risk by providing technical standards for accessibility. The Public Sector Bodies Accessibility Regulations 2018 reinforce this through specific procurement and statement requirements.