Equality minister Harriet Harman appeared unsure of one of her party’s commitments to gay rights last night.

Canvassing for the gay vote in Soho with Labour candidate Chris Bryant, Ms Harman was asked by PinkNews.co.uk whether she would match Tory leader David Cameron’s promise to strike out historic gay sex convictions.

Ms Harman first said she had not heard of Mr Cameron’s promise, which he made to PinkNews.co.uk readers last week, and said she would get back to us.

When a Labour Party aide pointed out that Labour’s commitment on the issue was in the party’s LGBT manifesto, Ms Harman would not say her party would match the Tories’ pledge.

Instead, she said: “The question is, is David Cameron going to actually change his view and match us on our commitment? I don’t think it’s a question of us trying to match David Cameron in any way, shape or form.”

The Labour LGBT manifesto promises that anyone convicted of a homosexual offence which was subsequently decriminalised would “have the opportunity to have their names removed from the sex offenders register and/or the police national computer on application.”

Mr Cameron said last week: “We will change the law so that any past convictions for consensual homosexual sexual activities, which have since become lawful, will be treated as spent, and will not be disclosed on a criminal record check when applying for a job.”

Like the Conservative Party, Labour’s promise to strike out historic gay convictions is not in its main policy document.

Other promises are that a Labour government will implement compulsory sex education, remove a ‘free speech’ amendment from homophobic hate crime laws and tackle homophobia and transphobia in schools and public services.

Ms Harman dismissed suggestions that Labour could lose the gay vote, but said gay people would have to fight to avoid “having the wool pulled over their eyes”.

She added: “It’s going to be a very close election, a very tight election. I think it’s going to be an election for people to fight for their rights.”

Ms Harman said that Tory leader David Cameron should have sacked his shadow home secretary Chris Grayling for telling a meeting that bed and breakfast owners should have the right to bar gay couples.

She said: “He thought that he could say that in private […] It’s very revealing. It shows what his true views are. Of course he should apologise but actually what the problem is is that’s what his view is.

“I think that makes him unsuited to be home secretary and David Cameron should not be prepared to have him in his shadow cabinet.”

Ms Harman was also asked about exemptions for faith schools on sex education and the failed amendment which would have clarified the law on who churches can employ.

The Children, Schools and Families Bill insists that all schools must include issues such as homosexuality, gay parents and HIV in the sex education curriculum. Faith schools may teach these subjects in line with their own beliefs, which some gay rights campaigners said could lead to children being told homosexuality is wrong.

In February, the government backed down over an amendment to the Equality Bill which would have clarified the law requiring churches only to discriminate in terms of sexual orientation when hiring those who will teach doctrine or lead worship. There were fears churches were continuing to refuse jobs to gay people.

Ms Harman said that the religious employment exemption applied only to “ministers, imams, priests and rabbis” and that the laws on churches employing for posts such as cleaners and administrative assistants were “very clearly drawn”.

On laws allowing faith schools to teach about homosexuality in line with their own beliefs, she said that Labour had put in clauses to ensure all children had at least one year of sex education but this was “chopped out at the last minute” by the Tories.