Regulations banning the donation of blood by men who have ever had gay sex will be lifted from today.

The Department of Health announced the changes in September, implementing a one-year deferral period instead, so that men who have had gay sex in the last 12 months may still not donate blood.

The change comes into force in England, Wales and Scotland this week.

Northern Ireland has not yet decided whether it will relax the rules, prompting an accusation of homophobia against its health minister.

The Advisory Committee on the Safety of Blood, Tissues and Organs (Sabto) carried out a review and found it could no longer support the permanent exclusion of men who have had sex with men.

Dr Lorna Williamson, NHS Blood and Transplant’s medical and research director, said: “Our priority as a blood service is to provide a safe and sufficient supply of blood for patients. This change gives us an opportunity to broaden our donor acceptance on the basis of the latest scientific evidence.

“The Sabto review concluded that the safety of the blood supply would not be affected by the change and we would like to reassure patients receiving transfusions that the blood supply is as safe as it reasonably can be and amongst the safest in the world. There has been no documented transmission of a blood-borne virus in the UK since 2005, with no HIV transmission since 2002.”

Gay rights campaigners said gay men would still be treated unfairly under the new rules implemented today, as heterosexuals engaged in higher risk sexual activity are not subject to the same restrictions.

The one-year deferral was chosen in part because of Hepatitis B, which disproportionately affects gay and bisexual men. While there is a four-week window between transmission and detection of HIV, Hepatitis B can take up to a year to be cleared by the body.

HIV charities generally welcomed the announcement, although they called for further reviews if the rates of HIV and Hepatitis B in gay men fall.

National AIDS Trust, Terrence Higgins Trust and GMFA said in a joint statement at the time of the announcement: “Whilst we are pleased to welcome this rule change for gay men, we will continue to encourage SaBTO to regularly review their restrictions on blood donation related to sexual behaviour (including other groups in addition to gay men). Particularly as the epidemics around blood-borne viruses evolve and scientific evidence changes and advances.”

The European Commission said that any ban on the basis of sexual orientation breaks EU laws.

But in response to a recent written question, John Dalli, the European Commissioner for Health and Consumer Policy, said that sexual behaviour should not be confused with sexual orientation.

Gay rights charity Stonewall said the change was a “step in the right direction” but called for donors to be screened purely on the basis of behaviour, rather than sexual orientation.

Chief executive Ben Summerskill said: “Safety must remain paramount. However at a time of national shortages in blood, everyone who can give blood at no risk to recipients should be able to donate.

“To retain a blanket ban on any man who has had sex with another man in the last year, even if he has only had oral sex, remains disproportionate on the basis of available evidence.”

He added: “Stonewall will continue to push for a donation system based on the real risks a potential donor poses. People wanting to donate blood should be asked similar questions – irrespective of their sexual orientation – that accurately assess their level of risk of infection. Sadly, the proposed new system will still fail to do this.”