HIV infection rates show steady fall over four years
26 November 2010 Last updated at 10:18 GMT
The number of new cases of HIV in the UK has fallen for the last four years, according to the latest figures.
But it is thought there may be more than twenty thousand people who are unaware they have the virus.
Paul Ward, who works for the sexual health charity the Terrence Higgins Trust, was diagnosed with the virus many years after he became infected.
He only had the test after collapsing on the street.
He told the BBC there was no logical reason for not being tested.