People who are concerned that they might have HIV can now legally test themselves in the comfort of their own homes.

Until now it has been illegal to do an HIV test at home and read the result — users could only take a sample themselves and send it off for testing in a laboratory.

But a change in the law, which came into effect yesterday, means people can perform a simple saliva test at home.

Terrence Higgins Trust medical director Michael Brady said that with HIV transmission in Britain largely driven by the 22,000 undiagnosed sufferers, anything that provided them with another option to test and access effective treatment was welcome.

He added: “It is vital that HIV self-testing kits offer high-quality information, including how to obtain practical and emotional support and how to quickly access specialist HIV services.”

No kit has yet met the stringent quality standards required for use in Britain.