The number of people living with HIV in the UK reached an estimated 91,500 in 2010, with a quarter of those unaware of their infection, according to Health Protection Agency figures published today.

The data, released by the HPA ahead of World AIDS Day on Thursday, also shows the highest ever rate of new infections.

More than 3,000 gay men were diagnosed with HIV last year, as part of 6,660 new infections in the population as a whole.

The 2010 figures mean 100,000 people may be living with the virus in the UK by the end of this year.

The statistics were said to show that one in 20 gay men are now infected with HIV nationally with one in 11 in London.

The HPA also said it was concerned that over half of those diagnosed last year had been “late” diagnoses, coming after the point at which treatment should have started, and leading to an increased risk of developing AIDS.

Paul Ward, Deputy Chief Executive of Terrence Higgins Trust, called the figures a “serious wake up call for gay men.”

“Thirty years ago, AIDS devastated gay communities across the UK, but also gave rise to an unprecedented community response.

“Effective drug treatments have made it possible for someone diagnosed with HIV today to live a long, healthy life, but that doesn’t mean we can take our foot off the gas in trying to stop its spread.

“HIV isn’t happening somewhere else or happening to other people; it’s happening right now, and the people who have or are at risk of contracting HIV are our friends, our lovers, and the guys who work on the scene. They are the men you meet at social groups, in saunas, online or on the dance floor. HIV affects all of us and it’s up to all of us to stop the spread of HIV in our community.”

One of the recommendations made by the HPA was the introduction of universal HIV testing.

One in five visitors to a sexual health clinic, the Agency says, refused a test.

Deborah Jack, Chief Executive of NAT said there was little need to fear HIV testing, given medical advances in detection and treatment.

She added: “We need to eradicate the fear around HIV testing – the test itself is a minor process which can nowadays be done through a finger-prick or saliva test – and if you are diagnosed with HIV, there is effective treatment available.

“It is always better to know your status and when it comes to having HIV, ignorance is definitely not bliss.

“People shouldn’t be scared of HIV testing, but they should be scared of undiagnosed HIV. The advances in HIV treatment have been one of the biggest success stories in the 30 years since the virus first emerged, but too many people test too late and so fail to benefit from these drugs.”

Dr Valerie Delpech, consultant epidemiologist and head of HIV surveillance at the HPA, said: “Research by the HPA has shown that routine and universal testing is feasible to undertake and acceptable to patients.

“Increased testing and greater access will help reduce the number of people who are unaware of their HIV status and increase the chances of early diagnosis, when treatment is more successful.”

Dr Delpech added: “Thanks to the development of anti-retroviral treatments and universal access to world class health care through the NHS, HIV is a manageable illness for the vast majority of people affected in this country.

“But an HIV diagnosis means a lifetime of medication and the costs of providing specialist HIV treatment and care are substantial and accelerating, so avoiding the infection altogether is essential for controlling the epidemic in the UK.

“If you are having sex, using condoms with any new or concurrent partners is the best way to prevent HIV. We encourage all people to take up the offer of an HIV test in whatever health care setting.”