Police officers will be asked to declare their sexuality, according to a new paper to be produced by Metropolitan Police Commissioner, Sir Ian Blair.

The policy, which will be presented to the equality committee of the Metropolitan Police Authority, is expected to set out plans to gain an accurate quota of gay and lesbian officers in the police force.

The document was revealed by the Daily Mail, it says, “Data on sexual orientation is not currently held and therefore no meaningful analysis can be undertaken, to address this, a self-service facility will be available in July which will enable staff to self-disclose their sexual orientation.”

It refers to a “disproportion between numbers of gay officers and numbers of homosexuals in the population. ‘It has been estimated that approximately ten per cent of the population is gay or lesbian.”

“However, in a city as cosmopolitan as London, this could be a considerable underestimate. The figures for the bisexual and transgender communities would be even harder to guesstimate.”

The system would be voluntary and anonymous, according to the paper.

But Conservative spokesman Nick Herbert accused Mr Blair of positive discrimination, he told the Daily Mail, “Sexual orientation is a private matter. If people want to disclose it voluntarily that is fine but they should not be forced or put under pressure to do so.”

“The principle that police should be representative of the community they serve – including sexual orientation – is the right one, but positive discrimination is not the way.”

The 2011 Census will contain a civil partnerships section but questions on sexual orientation have been saved for a separate nationwide government survey.