An increasing number of people in Britain are living with HIV/AIDS with most having been infected in places such as sub-Saharan Africa
The Health Protection Agency says around 63,500 UK adults were living with HIV in 2005 - with as many as a third unaware of their infection.
Most new HIV cases in 2005 were infected abroad, but more cases are being contracted in the UK, it said.
However, the HPA figures show a relatively small increase in new HIV diagnoses, compared to previous years.
The total number living with HIV in the UK in 2004 was 58,300.
The figures show there were 7,450 diagnoses in 2005, compared to 7,275 revealed in last year's HPA report.
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.
However, the increase among that group was small with an increase of around 50 new diagnoses compared to 2004.
Dr Valerie Delpech, an HIV expert at the HPA said: "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."
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