Boris leads Pride London parade

Mr Johnson has been accused of homophobia for comparing gay civil partnerships to marrying a dog. He also supported keeping Section 28 of the Local Government Act 1988, which banned local authorities from promoting homosexuality.

But the Mayor sought to put this behind him when he joined tens of thousands of Pride London marchers for a noisy and colourful procession through the heart of the capital this afternoon.

Mr Johnson received some boos as he led floats and performers to Trafalgar Square, but prominent gay campaigners said they would give him another chance.

Stonewall chief executive Ben Summerskill said: "All politicians are on a journey, and his journey seems to be in the right direction. That is hugely welcome to thousands of people. At the end of the day, as with all politicians, you have to judge them by what they do in office."

Ahead of the parade Prime Minister Gordon Brown discussed tackling homophobic bullying with actor Sir Ian McKellen and members of Stonewall in Downing Street.

His spokesman said Mr Brown was "delighted" to meet them and had wished them all the best for their Pride activities.

Sir Ian, one of Stonewall's co-founders, said meeting the Prime Minister at Number 10 was "hugely important". He added: "I am very pleased that he has listened to the concerns expressed by Stonewall, particularly around issues of homophobic bullying in schools, which still blights so many young people's lives."

This year's parade represented a landmark as for the first time members of all three Armed Forces were allowed to attend in uniform.

The event was addressed by Equality Minister Harriet Harman and Lib-Dem leader Nick Clegg.