This is an interesting case study in the challenges of creating an accessible design for the BBC iPlayer.
It may not seem immediately obvious, but visual design can have a massive impact on users who cannot see the page. I often find that mobile applications and websites that are problematic to make accessible are the ones where the visual design, by dictating structure, does not allow it.
This does not mean that standards and guidelines are redundant — far from it. But what we have found at the BBC is that standards need to sit within, and inform, an accessibility framework that runs through product management, user experience, development and quality assurance. As such, accessibility originates with UX. Most of the thinking and requirements should be considered up front so that poor accessibility isn’t designed in.