Statisticians summon the courage to ask: Are you gay?

The officials whose job is to count the number of people in the UK have finally overcome one of their last taboos and are going to collect statistics on how many people there are who call themselves gay.

All major government population surveys will now include a question about sexuality. Participants will be asked to classify themselves by putting a tick against one of four options: heterosexual/straight, gay/lesbian, bisexual, or "other".

But as in all government surveys, respondents will be entitled to refuse to answer the question, or put themselves down as "don't know".

It will mean that for the first time, there will be accurate statistics on the number of people there are in Britain who think of themselves as gay or bisexual. The best estimate at present is the figure used by Treasury actuaries, who believe that it is around six per cent.

The question about sexuality will now appear in the annual population survey, the labour force survey, and other major government surveys covering anyone aged 16 or above.

Karen Dunnell, the head of the Office of National Statistics, promised that the answers given about sexuality would be confidential. She added: "Better measurement of equality is essential, if we are properly to analyse, understand and address inequalities in society."

A spokesman added that the category "other" had been added to the question because statisticians believe that about one per cent of the population reject all standard categories such as gay, straight or bisexual.

The move was welcomed by Ben Summerskill, the chief executive of Stonewall, which campaigns for gay equality. "Getting the Office of National Statistics to take this issue seriously has been like pulling teeth," he said.

For many years, the number of gays in the overall population was a complete mystery, because to admit to homosexuality was to risk persecution or even, 40 years ago, criminal prosecution.