As a result, desperate young women are using fake blood and even going in for reconstructive surgery to fake their virginity, the investigative radio documentary reported. In an echo of social attitudes held in many parts of the Indian subcontinent, the programme found that most of the 17 to 21 year old men interviewed in the region of West Midlands - home to a large number of Asians - preferred women to be virgins at marriage.

Concepts of 'izzat' - or honour - are strongly held among some conservative Asian communities in Britain and have been linked not only to the practice of forced marriage but also, in some cases, the murder of young women. An adviser formerly with the national sexual health charity Brook said she personally received requests for information on faking virginity on a daily basis from young Asian women - and that she provided the information because she feared for the safety of these women.

She said: "They would sometimes come in to the centre because they were concerned about the fact that maybe they had had unprotected sex with a boyfriend and they were concerned about whether other men would know they had had sex before and were not a virgin.

"The discussions would then go around some of the myths around virginity... that girls bleed on the first time of having sexual intercourse. So we were able to say, 'lots of girls don't'.

"The problem is that lots of men and lots of people within the (Asian) community believe that that is true, and therefore they (young women) are very concerned that they will get married and they won't bleed and their husband will believe they weren't a virgin at marriage and all the problems that that would cause them in life."

She said women were using red dye and mock blood that can be bought from novelty shops that they inserted into their vaginas or spread on the bed sheet after having sex. One Pakistani woman said she knew someone who had used a bottle of red ink - and got away with it. "Her mother-in-law was very happy," said the woman.

Underlining the seriousness of the issue, the adviser said she agreed to provide information on how to fake virginity because "for some young women the risks to them and their personal safety were so great that if they were not able to fake it then the consequences could have been dire.""

A community worker who works with young Asians in west London said some girls have had to flee their homes and go into shelter "because their life is on the line. Somebody may have found out".

Linda Cardozo, a gynaecologist at Kings College Hospital in London, said some desperate Asian women were seeking reconstructive hymen-repair surgery, but that it was "quite difficult to achieve" the repair because there may not always be enough tissues to bring together.

In any case, there was no guarantee that the woman would bleed.

"The main aim of hymen repair is to bleed on wedding night, but of course there are many women who don't bleed on their wedding night, whether they are virgins or not.

"This is because the hymen may be very stretchy, they may have used tampons for menstruation, they may have had lot of exercise and subtle tissues and therefore there are many women who have their first intercourse without bleeding at all.

"So there's no guarantee these women will achieve the aim they set out to achieve," the doctor added.

Although some 24 such repairs had been performed in the state health sector, the vast majority of such surgeries are thought to take place in the private sector, which each surgery costs between 1,500 and 2,000 pounds. ($3,000-4,000)