Gay networking websites Gaydar and GaydarGirls say that estimates of 1.5 per cent of the population being gay or bisexual cannot be true as they have 2.2 million members in the UK.

Yesterday, the Office of National Statistics published a survey of 450,000 people – the second largest after the census – which suggested that only one per cent of British people are gay or lesbian and 0.5 per cent are bisexual.

However, the websites say their membership figures account for 6.7 per cent of the population – just above the government estimate of six per cent.

Yesterday’s figures suggested that there are approximately 480,000 gay men and lesbians and 245,000 bisexual people in Britain – 725,000 LGB people in total.

But the websites, which offer members the chance to meet for dating and sex, say 2,185,072 British men and women have registered with them.

Trevor Martin, managing director at Gaydar said; “The Office for National Statistics figures don’t add up. With 2.2 million Gaydar profiles in the UK either there are a lot of straight guys playing away from girlfriends or every single gay and lesbian in the country tunes into GaydarRadio – or the ONS have got it terribly wrong.”

The 1.5 per cent figure has already been used by some figures to question government efforts to tackle homophobia.

Mike Judge, of the Christian Institute, said: “A large amount of public money has been spent on the basis of higher figures, which have turned out to be a lie.”

Conservative MP Philip Davies added: “An awful lot of focus in diversity issues is given to people’s sexual preference and this difference is not as widespread as believed.”

Yesterday, gay lobby group Stonewall said the figures were likely to be an underestimation because many gay people may be unwilling to identify themselves as gay in a survey.

Spokeswoman Ruth Hunt said she would expect to see the figures rise as asking about sexual orientation becomes more commonplace.

In the national survey, 95 per cent of respondents said they were heterosexual.

Nearly four per cent of those asked refused to answer, said they did not know or described themselves as “other”.

Of the five per cent who did not say they were heterosexual, one per cent said they were gay or lesbian, 0.5 per cent said they were bisexual and 3.5 per cent refused to answer the question, described themselves as “other” or said they did not know.

Stonewall and the government both use a figure of six per cent of the population being lesbian, gay or bisexual, which works out at 3.6 million people.

This figure comes from 2005 research by the Department for Trade and Industry.

Other studies on sexual orientation have found that the figure varies between six and ten per cent.