Same-sex couples living in England and Wales can for the first time register for a legal wedding today, with the first ceremonies being held on 29 March this year, reports the BBC.
The UK Parliament voted last year to legalise same-sex marriages as they passed the Marriage (Same Sex Couples) Act 2013. The Act legalises same-sex marriage in the UK for the first time.
Same-sex couples who had to travel abroad to marry will also, from today, be able to have their foreign marriage legally recognised in the UK.
In future it will also be possible for those who entered into a legal 'civil partnership' to convert their relationship status to one of marriage.
Churches will be able to decide whether to opt-in to conducting same-sex services; however, part of the terms of the deal to legalise same-sex marriage saw the Churches of England and Wales locked out of performing such ceremonies.
Both churches are subject to a quadruple lock, making it illegal for them to conduct same-sex marriages, and making it impossible to challenge the inequality of this provision in UK law.
The Catholic Church will not permit same-sex marriages either.
The BBC interviewed one same-sex couple who married in Canada and who fought to have their marriage recognised by UK law for many years. Professor Celia Kitzinger, said the UK had been slow to adopt the law.
"We're the 15th country in the world, so it's been a bit slow and behind countries you would be quite surprised about," she told the BBC.
Scotland has also legalised same-sex marriage, and ceremonies are expected by the end of the year.