A drug that prevents the transmission of the HIV virus will be available in England from April, the Department of Health has confirmed.
PrEP - or pre-exposure prophylaxis - is an antiretroviral medicine which, taken once a day, stops the transmission of HIV during unprotected sex.
The pill is already available in Scotland and Wales to people at risk of contracting the virus.
It is estimated there are about 103,800 people living with HIV in the UK.
Health Secretary Matt Hancock said the roll-out of the drug in England would eliminate new HIV infections within 10 years.
NHS England will pay for the drug.
The cost is estimated to likely be much less than the lifetime bill for treating those who already carry the virus.
The Terrence Higgins Trust, a charity that supports those living with HIV, estimates that about 7% of the roughly 103,800 people living with the virus in the UK do not know they are HIV positive.
Ian Green, Chief Executive at the Terrence Higgins Trust, described the development as a "game-changer" for HIV prevention.
But he said more work needed to be done to ensure the benefits of PrEP were made clear to groups other than gay and bisexual men, such as women, trans people and BAME communities.
Sir Elton John, whose foundation supports HIV prevention and treatment, welcomed the government's decision.
"Taking PrEP prevents HIV from being passed on, which is truly incredible," he told the Sunday Times.
"It is the right decision for the UK government to roll this out more widely to minimise the spread of this disease so more people are protected - which is critical in fighting any epidemic."
What is PrEP?
- A pill taken daily, or on demand prior to having sex, to prevent HIV infection
- If taken consistently, when a condom is not worn and someone comes into contact with HIV, it protects cells in the body and disables the virus to stop it multiplying
- A UK Medical Research Council-run study comparing gay men on PrEP against non-users found an 86% fall in new HIV infections in PrEP users
- Many in the sexual health sector say PrEP, when taken correctly, is almost 100% effective
- It is aimed at men who have sex with men without a condom as well as others at high risk, including HIV-negative partners of individuals with HIV that is not virally suppressed
- Researchers are assessing demand for the drug and its effect on the number of new HIV infections
But PrEP does have its critics, with some commentators saying funding it will lead to an abdication of personal responsibility, with men choosing not to use condoms.
Unlike condoms, PrEP does not protect against other sexually-transmitted diseases such as syphilis and gonorrhoea - of which the numbers of infections are rising.
In 2018, new HIV diagnoses in the UK fell to their lowest level since 2000 - 4,484 people - due to the success of preventative measures, Public Health England said.
The decline has been attributed to a mix of prevention methods, such as testing, condom provision, and the wider use of PrEP.