The British HIV Association (BHIVA) Conference last week head that almost half gay men in the UK with HIV are unaware of their condition.

This year, the annual conference had set out to determine why so many men remain undiagnosed. The final session of the conference was held in conjunction with the British Association for Sexual Health and HIV (BASSH).

A survey of men in gay venues in London, Brighton, Manchester, Glasgow and Edinburgh found that 40% of men who tested positive for HIV thought they were HIV negative.

The most recent report by the Health Protection Agency said that although the proportion of gay men who take HIV tests as part of their general sexual health check has almost doubled to 85% since 1998, the number of men who leave without having their HIV infection diagnosed has decreased to 45% over the same time period.

This, experts conclude, means that the gay men who are at the greatest risk from HIV infection are also the least likely group to have an HIV test.

There was also evidence given that nearly 50% of gay men diagnosed with HIV this year are likely to have become infected since 2007.

Professor Andrew Phillips of the Royal Free and University College Medical School in London said that the results of the studies are due to the fact that the HIV infection rate amongst some gay men is so high that yearly tests are failing to pick up more recent infection.

He said: “People are not necessarily resistant to testing, they just need it frequently.”