Web design company Headscape, which has done work for the Learning and Skills Council, and universities, says further education is failing to meet even the minimum standards of accessibility.
It tested more than 200 college homepages and found, in 54 per cent of cases, they were "non-compliant" with the minimum standards of accessibility.
Paul Boag, creative director of Headscape, believes these websites are unlawful and would be censured by the courts if legal action were taken under the Disability Discrimination Act.
He said: "If someone did prosecute, in my opinion it (the college) would fall foul of the legislation.
"The act says that if you are providing a service, that service has to be accessible to people with disabilities. Websites are a service."
The survey also found 39 per cent of university homepages were non-compliant.
At the time of testing, 37 college sites and nine university sites were down altogether - with no access at all.
A spokesperson for the Association of Colleges said: "Some colleges will not have the in-house expertise to ensure compliance, but need to be aware that guidance is available from a variety of reliable sources."
The homepage of the Learning and Skills Council website, which was not covered by the survey, meets the legal requirements, according to Mr Boag, although he says the quango's "corporate" channel does not.
The LSC refused to comment.
Websites, he says, should be designed so they are easy to read for those with limited vision and can be used along with special software that allows blind people to "hear" the text by moving the cursor around the page.
Some websites offer text-only versions without the graphics although these are sometimes seen as poor versions of the original.
The software can be used to allow blind people to detect words contained in graphics, such as headings and logos.