The web sites of the England's 20 Premiership football clubs are failing to meet minimum accessibility standards on their web sites, effectively barring millions of disabled people, and potentially breaking the country's Disability Discrimination Act.

The findings are from a survey published this month by national computing and disability charity AbilityNet, and are broadly in line with findings from earlier AbilityNet surveys into web sites operated by leading airlines, newspapers, banks and supermarkets

The 20 sites were audited and checked for accessibility using a series of both manual and automated tools. But not one of them satisfied the criteria required to facilitate access for users with visual impairment, dyslexia or those with a physical disability making mouse use difficult.

The report reveals that only Manchester United's alternative 'accessible' web site achieved more than a one star rating. However its two stars still fall short of the three star minimum required to achieve what AbilityNet considers to be a basic level of accessibility.

"It is illegal to bar disabled visitors from on-line services offered to the general public," said Robin Christopherson, AbilityNet's Web Consultancy Manager, himself blind. "Whilst no organisation would knowingly impose a 'technological lock-out' on their disabled customers, it is clear that there is still much scope for improvement."

Christopherson congratulated Man U on launching it's 'alternative' site, but criticised both the link to the site, which can easily be missed, and the fact that even this site, the best of the bunch, did not comply with a basic level of accessibility. He also queried whether using an alternative site was actually the best way forward.

"At AbilityNet we subscribe to the opinion that an organisation's main web site can and should be accessible to the broadest audience possible," he said.

"Recently published research [The Web: Access and Inclusion for Disabled People] by The Disability Rights Commission shows that able-bodied visitors also benefit from accessible web sites, finding them easier and quicker to use by some 35%, so the commercial argument is overwhelming."

This is consistent with guidance from the Royal National Institute for the Blind: it argues that separate accessible sites, or text-only versions, should be avoided whenever possible, simply because being treated differently can reinforce the feeling of marginalisation that someone with a disability experiences. From a business perspective, the RNIB points out that it also leads to dual maintenance of content, which is far from ideal.

All the clubs reviewed were invited to make a public commitment to accessibility and to date, Everton, Chelsea and Premium TV (which hosts the sites of 10 of the clubs: Aston Villa, Birmingham City, Blackburn Rovers, Bolton Wanderers, Crystal Palace, Middlesborough, Newcastle United, Norwich City, Portsmouth and West Bromwich Albion) have pledged to improve standards.

Typical problems encountered by Christopherson and his team include the hard-coding of the text size on some sites, particularly in relation to headings and links, meaning that they cannot be easily enlarged, and thus impairing the access afforded to many visitors with a vision impairment.

The text labels attached to images upon which blind visitors and text browser users rely for an explanation are often uninformative or completely absent, says AbilityNet. Without these spoken labels on graphical links, navigation for a blind visitor is pure guesswork.

AbilityNet also found overuse of pictures of text instead of actual text. This not only means that the user cannot modify font size or colour contrast, it also prevents screen reader users from reading the content when so often these images also do not carry tool tips – spoken description of pictures.

Another common problem identified by the survey was the inclusion of adverts and features made up of moving images that will be distracting for visitors with a cognitive impairment, together with Flash movies, which can present access problems for visitors who cannot use a mouse, are vision impaired or who use speech output or voice recognition software.

Other drawbacks common to several of the sites tested include the reliance on JavaScript – small programs that are built into a page and often not recognised (and therefore rendered unreadable) by many older browsers, or some specialist browsers used by those with vision impairment – and the use of the club strip as a colour scheme, which makes the text difficult to interpret for those with colour deficit conditions, vision impairment or dyslexia.

"The internet has changed the way we access goods and information beyond recognition," said Shuna Kennedy, AbilityNet's chief executive.

"Premier League Clubs have the opportunity to set the standards for clubs overall: a web site through which disabled fans can book tickets or find out about the latest match fixtures isn't only a matter of commercial logic and moral duty; like other suppliers of goods and services, football club web sites must comply with equal access laws under the provisions of the Disability Discrimination Act," she continued.

AbilityNet warns that these sites are excluding a hugely valuable potential market with an estimated total spending power of over £120 billion a year.

We are processing your request. \n Thank you for your patience. An error occurred. This could be due to inactivity on the page - please try again.