Gay and bisexual men will be able to donate blood within three months of sexual activity instead of 12 months, the UK government has announced as part of a wider reform of lesbian, gay, bisexual and transgender (LGBT) laws.

Men who have sex with men are currently barred from donating blood for a year following their last sexual encounter in order to reduce the risk of transmitting HIV, the virus that causes AIDS.

The government, which will implement the changes from early 2018, said the decision to relax the donation period was based on the latest scientific evidence and medical advances and could increase the blood donor supply across the country.

The decision to relax the donation period was based on the latest scientific evidence and medical advances

"This government is committed to building an inclusive society that works for everyone, no matter what their gender or sexuality and we're taking the next step forward," said Minister for Women and Equalities Justine Greening in a statement.

Ethan Spibey, founder of campaign group FreedomToDonate, said in a statement that the move "marks a world-leading blood donation policy for gay and bisexual men and the other groups previously restricted".

Greening has also proposed changes to the Gender Recognition Act to allow gender reassignment surgery without a medical diagnosis of gender dysphoria, a mental health condition where someone's gender identity does not match their physical body.

Apart from a medical diagnosis, transgender people must also prove they have been transitioning for two years before they are allowed to undergo gender reassignment surgery.

LGBT advocacy group Stonewall said the current rules were intrusive and demeaning and needed reform.

"It's vital that this reform removes the requirements for medical evidence and an intrusive interview panel, and finally allows all trans people to have their gender legally recognised through a simple administrative process," said Suzanna Hopwood, a member of the Stonewall Trans Advisory Group.