Wedding rings are swapped by same-sex couples for the first time when the Marriage Act makes same-sex marriage legal in England and Wales, with Scotland following suit a few months later.
The first ceremonies took place in England and Wales on 29 March 2014, with same-sex couples vying to claim the title of being the first to be married in Britain by timing their vows to finish just as the clock struck midnight.
David Cameron, prime minister at the time, wrote in Pink News that the reform was necessary because "when people's love is divided by law, it is that law that needs to change. The introduction of same-sex civil marriage says something about the sort of country we are. It clearly says 'you are equal' whether straight or gay. That is so important in trying to create an environment where people are no longer bullied because of their sexuality - and where they can realise their potential."
Ruth Hunt, then Stonewall’s acting chief executive, said the day was "a momentous day for England and Wales, as the first same-sex marriages mark full legal equality for lesbian, gay and bisexual people. The first weddings will send a powerful message to every person in Britain and around the world that you can live and love as you choose, regardless of your sexual orientation."
Rainbow flags flew at the Cabinet Office in Westminster and the Scotland Office. Same-sex marriage was passed by the Scottish Parliament in February 2014 and became law on 16 December 2014. Same-sex marriage is still not legal in Northern Ireland.
In the first 48 hours after the law came into force, 95 same-sex marriages took place; around 15,000 took place in England and Wales between March 2014 and October 2015, according to the Office of National Statistics.
Same-sex marriage was passed by the Scottish parliament in February 2014 through the Marriage and Civil Partnership (Scotland) Act 2014, with the first same-sex weddings taking place on 31 December 2014.
Colin Macfarlane, director of Stonewall Scotland, said: "This historic change in the law is the result of a tireless campaign by many organisations, including Stonewall Scotland, parliamentarians and individuals to ensure that same-sex couples can enjoy full equality before the law.
"While there is still lots to do before the lived day-to-day experience of many lesbian, gay, bisexual and transgender people is truly equal in Scotland, this is a day of celebration and what better way to celebrate Hogmanay by saying I do to equal marriage."