The NHS has the power to pay up to £20m ($25m) a year to fund a drug that will prevent thousands of people at "high risk" from contracting HIV, the Court of Appeal has ruled. The court upheld a High Court judgement that NHS England can cover the cost of providing around 10,000 people with Truvada for PrEP (pre-exposure prophylaxis).

The risk people are deemed at risk of contracting HIV because their partners have the infection. Making the drug available on the NHS has been described as a "game changer" in fighting the disease, as PrEP can reduce the risk of infection by more than 90% when taken correctly.

The High Court had previously ruled that the NHS should provide the drug because they are responsible for preventative health. The court decision, the NHS says, could lead to cuts in funding for nine other treatments.

Critics say that at £400 per person per month, the drug is too expensive and those at risk should be encouraged to practice safe sex. Treatments which could be cut include a drug to help children with cystic fibrosis breathe, prosthetic limbs for amputees and hearing implants for deaf people.

truvada prep
People at risk of contracting HIV because their partners are infected may soon be able to freely access Truvada on the NHS Justin Sullivan/Getty Images

But Deborah Gold, chief executive of National Aids Trust (NAT), said the drug can actually save the NHS money. She said: "We are delighted to have been vindicated by the court a second time. HIV is a critical issue in the UK where over 4,000 people acquire HIV every year.

"PrEP works, it saves money, and most importantly it has the power to prevent HIV acquisition for thousands of people, at the same time as beginning to end the HIV epidemic. This judgement brings that possibility one step closer."

NHS England said they would not appeal the decision and would now formally consider the funding of the drug treatment. A spokesperson said the judgement confirmed that the NHS had the ability, but not the obligation, to fund the drug.

They added: "We will discuss with local authorities how NHS-funded Prep medication could be administered by the sexual health teams they commission ... We will immediately ask the drug manufacturer to reconsider its currently proposed excessively high pricing, and will also explore options for using generics."