David Cameron says more needs to be done to increase HIV testing and has paid tribute to HIV/AIDS care and prevention workers in his annual World AIDS Day message.

In his video message, the Prime Minister said: “As we mark World AIDS Day, I want to add my voice once again to all of those who are working so hard to raise awareness of AIDS, to challenge stigma, and to support those living with HIV, to have full and productive happy lives.

“Thanks to effective treatment and the brilliant care of our NHS, an early diagnosis means the outlook for most people today with HIV in the UK is a good one.

“But some 25,000 people in the UK do not know they have it, or not benefiting from treatment, and are increasing the risk of passing the virus on.

“This means up to 600 people each year could be dying from a preventable, treatable condition”.

David Cameron then went on to mention the story of the Terrence Higgins Trust.

This year THT is marking its 30th anniversary.

The charity, which held a reception at London’s City Hall on Monday, was set up in 1982 after the death of Terry Higgins – a gay Hansard reporter in the House of Commons and barman at the Heaven nightclub.

Terry was among the first people known to die of an AIDS-related illness in the UK.

In his video, Labour leader Ed Miliband said: ”Whether it affects people in Britain or around the world, that fight is an incredibly important fight. It’s a fight I join with.”

“It’s also a moment when we recognise the stigma faced by those people with HIV or AIDS. Let’s stand up for their rights, let’s up for inclusion in our society and let’s stand up for prejudice wherever we find it.”

Liberal Democrat Deputy Prime Minister, Nick Clegg said:”1 in 5 people who disclose that they have HIV are discriminated in the work place. This is simply unacceptable in 2012. People living with HIV have the same rights as everyone else.”

He ended by saying: “Today on World Aids Day, we can look back at our achievements and recognise that more progress needs to be made. Lets world together in the United Kingdom and around the world to create a world that is free finally of HIV.”

In a letter to mark World AIDS Day, Prince William and Prince Harry said: “The fight against HIV started 30 years ago. Our generation must pick up the sword and continue the fight. There is still no cure or vaccine. However, we know it is possible to prevent HIV from spreading further in the future.