Around a third of the 73 000 adults in the United Kingdom who now have HIV remain unaware of their infection, despite a big increase in the number of people being tested, the latest figures from the Health Protection Agency indicate.

The agency's annual report on HIV and other sexually transmitted diseases shows that the number of new infections of HIV fell a little last year, from 7900 in 2005 to an estimated 7800. But the incidence among gay men continues to rise, with 2700 new cases reported in 2006—nearly two thirds of all HIV infections thought to have been acquired in the UK.

The incidence of other …