David Cameron attended a private Pride party last night hosted by openly gay Conservative candidate Margot James.

However, the Conservative leader will not be attending the Pride parade on Saturday due to “constituency events”, his spokeswoman said.

This means that three of the most prominent politicians in the country will not attend the event, as prime minister Gordon Brown has said he will not attend due to security considerations and London mayor Boris Johnson, who led the march last year, has said the date clashes with his son’s birthday.

Cameron’s spokeswoman said it had always been known he could not join Saturday’s march and so had chosen to attend the private party instead.

Giving a speech at the the Pride at Paramount event last night, Cameron said his attendance was a sign of how the Conservative Party had changed.

He said: “Just think if ten years ago a Conservative candidate had suggested holding a fundraiser as part of Gay Pride week. I’m not sure they’d have got many Conservatives to attend… and I’m not sure there would have been many gay people there either.

“But here we are this evening, standing side by side. It is a sign of how our society is changing. It’s a sign of how much the Conservative Party has changed.”

He spoke of using “positive action” to encourage more gay, female or ethnic minority candidates to join the party, saying: “An open door is not exactly inviting to a young black candidate if all they see is a group of white, middle-aged Conservative men inside.”

Cameron paid tribute to the work of Tony Blair’s Labour government on gay rights, such as equalising the age of consent, lifting the military gay ban and introducing civil partnerships, but said the next step was changing attitudes and implementing “cultural change”.

Continuing to reference the party’s new slogan ‘Now for Change’, the Tory leader concluded: “That’s the kind of change we need today. That’s the kind of change the new, compassionate Conservative Party understands.

“And together, as politicians and individuals, we can bring about that change. No to bigotry and prejudice. Yes to responsibility and equal rights. It’s a change worth fighting for.”

Last month, we asked readers whether they thought the Conservative party was becoming more gay-friendly. While 37 per cent of PinkNews.co.uk readers said it was, 63 per cent believed the party had not changed.

However, 39 per cent of respondents said they planned to vote Tory in the next general election, compared to only 29 per cent for Labour.