Thousands of revellers have marched through central London on the annual Pride parade.
Organisers hailed this year's event as the city's biggest lesbian, gay, bisexual and transgender celebration for more than a decade.
The 2013 Pride in London parade began at Baker Street and passed through Oxford Street, Piccadilly and Trafalgar Square before ending at Whitehall.
This year's fancy dress theme was Love and Marriage - to coincide with the Equal Marriage Bill currently before Parliament.
Writing in the official Pride guide, Prime Minister David Cameron said equal marriage reforms would allow gay schoolchildren to "stand a little bit taller".
The Prime Minister told how he hopes youngsters would be able to see that Parliament "believes their love is the same as anyone else's love" as thousands of people prepare to descend on the capital for the annual gathering.
Mr Cameron said: "There will be girls and boys in school today who are worried about being bullied and concerned about what society thinks of them because they are gay or lesbian. By making this change they will be able to see that Parliament believes their love is the same as anyone else's love and that we believe in equality.
"I think this will enable them to stand that bit taller, be that bit more confident and I am proud of that."
Deputy Prime Minister Nick Clegg wrote: "Many straight people have argued for the reform [of equal marriage] with as much passion as gay people. Why? Because this isn't just about technical changes or legal definitions. It isn't just a 'gay issue'. It's about the kind of society we wish to be."
Labour leader Ed Miliband said there is "still more to be done" to change attitudes. He added: "Too many young people still fear to come out at school due to bullying. In too many places in the world, it is still a crime to be gay."
Michael Salter, chairman of Pride in London, said: "Pride in London is a great opportunity to promote a charity or community group and campaign. This year the theme is Love (and Marriage) to celebrate civil partnerships, parents' love for their children, love of friends and family but it also recognises the Equal Marriage bill going through Parliament."