A longstanding safeguard which prevents blood being donated by men who have ever had sex with other men has been lifted.
Since the 1980s the lifelong safeguard has been in place to prevent the risk of HIV contamination.
But from 7 November men whose last sexual contact with another man was more than 12 months ago will be allowed to donate blood in England, Scotland and Wales.
A 12-month safeguard remains in place because men who have sex with men (MSM) have, as a group, a higher risk of sexually acquired blood-borne viruses.
Although all blood is tested for HIV and other diseases, there is a “window period” in which new infections cannot be detected.
Homosexual lobbyists welcomed the end of the lifetime safeguard, but criticised the new 12-month rule. Peter Tatchell demanded that the safeguard be completely removed.
The move came after a review by the Advisory Committee on the Safety of Blood, Tissues and Organs (SaBTO). It advises Health Ministers on blood safety.
Professor Deirdre Kelly, from SaBTO, said the review “examined the best available scientific evidence for UK blood donor selection in relation to sexual behaviours”.
But she added that donors must not give blood if they fall outside of the donor selection criteria.
The UK’s largest HIV and sexual health charity, the Terrence Higgins Trust (THT), said the blood safeguard was “a public health issue, rather than one of homophobic discrimination”.
Sir Nick Partridge, chief executive of the THT, noted: “The remaining deferral regulation for sexually active gay men is based on their heightened risk, as a group, of sexually acquired blood-borne viruses.”
However he also told the BBC it was impossible to say how many men would actually be able to start donating blood as “the vast majority of gay men are still [sexually] active”.
In Northern Ireland, its blood service is still considering the new recommendations.
Homosexual lobby group Stonewall said the move “remains disproportionate”.
And homosexual rights campaigner Peter Tatchell said the 12 month safeguard is “still excessive and unjustified”.
Mr Tatchell said: “Men who use condoms every time without breakages – and who test HIV negative – should not be barred from donating blood.”