UK firms have been warned that they face legal action and the threat of unlimited compensation payments if they fail to make websites accessible for people with disabilities.

An investigation of 1,000 UK-based websites by the Disability Rights Commission (DRC) found that 81 per cent are failing to meet the most basic needs of disabled people.

The DRC has warned that unless businesses improve accessibility, it will not hesitate to take legal action. Firms that continue to discriminate could face unlimited compensation payments under current legislation.

The "appalling" record of British firms in this area made it "highly likely" that court cases would be brought, said the DRC.

"Our approach has always been to work with industry," said Bert Massie, chairman of the DRC.

"But our research showed not a single website went to the [highest accessibility] standard. Potentially, every website owner in this country could be liable."

The World Wide Web Consortium has three levels for grading how accessible sites are for the disabled. The DRC study compared UK sites against these grades.

According to Professor Helen Petrie, who conducted the study, introducing a few basic tests to check accessibility of websites would alleviate the majority of the problems for disabled people. And there are further benefits for business, she added.

"We found that if you design sites for disabled people, you automatically design a site that is usable for everyone," she said.

Julie Howell, digital policy development officer at the RNIB, said: "Businesses have a social responsibility and a legal duty to ensure that disabled people can use their websites.

"The DRC findings would indicate that there is a need for additional government initiatives and resources to make businesses aware of what they must do to reach disabled customers."

The DRC recommends that firms should create written policies for creating accessible websites, involve disabled users in the design process from the earliest stages, and not rely on automated accessibility testing.

Other recommendations are aimed at the developers of testing and design tools and suggest that more consideration should be paid to functionality.