Who Is Accessibility For?
The common assumption: accessibility is for people with disabilities. This is true but incomplete.
Consider the "curb-cut effect" - the phenomenon named for how pavement kerb cuts designed for wheelchair users turned out to benefit parents with pushchairs, people with luggage, delivery workers, cyclists, and elderly pedestrians. Designing for the margins improves the experience for everyone.
Closed captions, designed for the deaf, are used primarily by people watching in noisy environments or in a second language. High-contrast modes, designed for the visually impaired, are preferred by many people on low-quality screens or in bright sunlight. Voice interfaces, designed for motor impairments, are used daily by millions of able-bodied people.
The Numbers
The World Health Organisation estimates that 1.3 billion people - 16% of the global population - experience significant disability. In the UK, that's approximately 14.6 million people, with a combined spending power of £274 billion (the Purple Pound).
By not designing accessibly, a business is voluntarily excluding a segment comparable in size to a major demographic.
WCAG: The Standard
The Web Content Accessibility Guidelines (WCAG) 2.1 define accessibility across four principles: content must be Perceivable, Operable, Understandable, and Robust (POUR).
The three compliance levels - A, AA, and AAA - set minimum thresholds. UK public sector organisations are legally required to meet AA compliance. Most international accessibility lawsuits cite AA failures.
AA compliance requires: sufficient color contrast (4.5:1 for body text), keyboard navigability (no mouse required), alt text for all meaningful images, proper heading hierarchy, form labels, and focus indicators.
Semantic HTML Is Accessibility Infrastructure
Most accessibility issues start with the same root cause: non-semantic HTML. A '<div>' styled to look like a button is not a button to a screen reader. A heading rendered as '<div class="big-text">' isn't in the document outline.
Semantic HTML - using '<button>', '<nav>', '<main>', '<h1>–<h6>', '<article>', and '<section>' for their intended purposes - provides the document structure that screen readers, search engines, and other assistive technologies depend on.
The SEO Connection
Google's crawlers are, in many ways, the most important screen reader on the internet. They read alt text, traverse heading hierarchies, interpret ARIA labels, and favour fast, navigable pages.
The overlap between accessibility best practices and SEO best practices is substantial. Improving one tends to improve the other. Both are downstream of the same root concern: does this content make sense without the visual layer?
The Legal Reality
Accessibility lawsuits are rising sharply. In the US, web accessibility lawsuits under the ADA have grown from under 2,000 in 2018 to over 4,600 in 2023. The UK Equality Act and European Accessibility Act create parallel liability.
The most common targets are e-commerce sites, banks, and educational institutions. The most common failures are missing alt text, unlabelled form fields, and keyboard traps.
Building accessibly is not just an ethical choice. It is, increasingly, a legal requirement.
