An "increasing pool" of people in the UK are living with HIV and Aids, official statistics show.
The Health Protection Agency says around 63,500 UK adults were living with HIV - with as many as a third unaware of their infection.
Most new HIV cases were infected abroad, but more cases are being contracted in the UK. The HPA figures show a relatively small increase in new HIV diagnoses, compared to previous years.
Two thirds of all new cases diagnosed last year were in people who contracted HIV in other countries where the virus is more prevalent, such as sub-Saharan Africa. A third were among gay and bisexual men.
Dr Valerie Delpech, an HIV expert at the HPA says: "We are seeing an ever increasing pool of people living with HIV and Aids in the UK. This is due to people living longer with HIV due to advances in treatment, sustained levels of newly acquired infections in gay men, further diagnoses among heterosexuals who acquired their infection in Africa, and cases being picked up earlier. Despite some improvements we are also concerned that many HIV infections are still being diagnosed late, so that life expectancy is reduced as treatment is not begun when required.
Will Nutland, of the Terrence Higgins Trust, says: "Over the last five years, we have seen some very steep increases in new HIV cases. Whilst figures have risen this year, the rate of acceleration of increase is much slower. Over two-thirds of diagnoses we see are from people who acquired their infection outside the UK. A third are men, gay and bisexual, most of whom acquired HIV in the UK.“