More gay and bisexual men will be allowed to donate blood, platelets and plasma after "historic" new rules came into effect.
The new eligibility rules came into force today on World Blood Donor Day and mean that donors in England, Scotland and Wales will no longer be asked if they are a man who has had sex with another man, NHS Blood and Transplant said.
Instead, any individual who attends to give blood regardless of gender will be asked if they have had sex and, if so, about recent sexual behaviours.
Anyone who has had the same sexual partner for the last three months will be eligible to donate, meaning more gay and bisexual men will be able to donate blood, platelets and plasma while keeping blood just as safe, NHS Blood and Transplant said.
The organisation's chief nurse for blood donation, Ella Poppitt, said: "Patient safety is at the heart of everything we do.
"This change is about switching around how we assess the risk of exposure to a sexual infection, so it is more tailored to the individual.
"We screen all donations for evidence of significant infections, which goes hand-in-hand with donor selection to maintain the safety of blood sent to hospitals.
Watch: Woman who lost job over transgender views wins appeal against employment tribunal
"All donors will now be asked about sexual behaviours which might have increased their risk of infection, particularly recently acquired infections. This means some donors might not be eligible on the day but may be in the future."
The changes to the donor safety check form will affect blood, plasma and platelet donors but the process of giving blood will not change.
NHS Blood and Transplant said eligibility will be based on individual circumstances surrounding health, travel and sexual behaviours shown to be at a higher risk of sexual infection.
Under the changes people can donate if they have had the same sexual partner for the last three months, or if they have a new sexual partner with whom they have not had anal sex and there is no known recent exposure to a sexually transmitted infection (STI) or recent use of pre-exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP).
Anyone who has had anal sex with a new partner or with multiple partners in the last three months will not be able to give blood but may be eligible in the future.
The changes were welcomed by charities including the National Aids Trust, Stonewall and Terrence Higgins Trust.
However, the Terrence Higgins Trust said the government had kept a "discriminatory restriction" in England which will affect black communities' ability to give blood.
The restriction relates to a three-month deferral period for anyone who has a "partner who has, or you think may have been, sexually active in parts of the world where HIV/Aids is very common" and references "most countries in Africa", the charity added.
To become a blood donor, register and book an appointment by calling 0300 123 2323, downloading the GiveBloodNHS app, or visiting www.blood.co.uk.
Watch: New UK special envoy on LGBT+ rights Lord Herbert admits worries of 'culture war' over trans rights