One in every 1,000 people aged 15-49 in the UK is infected by the HIV virus, which can lead to Aids, according to latest estimates.

The Public Health Laboratory Service says that the number of people living with diagnosed HIV infection is increasing by at least 10% a year.

Dr Angus Nicoll, Acting Director of the PHLS Communicable Disease Surveillance Centre, said: "This is a worrying figure.

1999 now looks set to have the highest number of UK HIV diagnoses not just for the 1990s, but ever

Dr Angus Nicholl, Public Health Laboratory Service

"Although the 1 in 1000 figure is much lower than, for example, countries in sub-Saharan Africa there is no cause for complacency in the UK."

In parts of Africa one in five people is infected with HIV.

Dr Nicholl said the PHLS had identified combating HIV as a top priority.

"HIV is an entirely preventable infection, and yet new infections continue to occur and, allowing for late reports which are still to come in, 1999 now looks set to have the highest number of UK HIV diagnoses not just for the 1990s, but ever."

Dr Nicholl stressed that although drugs were now available to slow the progression of disease, there was still no cure for HIV.

He said prevention was the key to successfully checking the spread of the disease in the UK.

"It is vital that we reinvigorate our prevention campaigns and reinforce the importance of safer sex messages in the forthcoming new government Sexual Health and HIV strategy."

The PHLS is particularly concerned that the level of risk taking appears to be increasing.

The proportion of injecting drug users who report sharing injecting equipment has increased by over 30% since 1997.

In addition, diagnoses of other sexually transmitted infections, notably gonorrhoea and syphilis, are rising - suggesting more people are having unsafe sex.

The PHLS will present information about HIV in the UK to the International Aids Conference starting in Durban, South Africa, starting on Sunday.