Police and health professionals have warned that a growing number of female circumcisions are being carried out in Britain even though the practice is illegal.

Experts estimate that between 500 and 2,000 UK girls face genital mutilation this summer, when they can be "cut" during the school break without anyone questioning their absence. Female genital mutilation involves the cutting off of girls' external genitalia, including the clitoris. Some 63,000 women in the UK have suffered genital mutilation and 20,000 girls are at risk.

The practice was outlawed in Britain in 1985 and taking children out of the country to have it performed was made illegal in 2003.

But the Observer has been told there is evidence it continues unabated among communities with links to African, Arab and Asian countries, and "cutting parties" are going on behind closed doors in Britain.

Jackie Mathers, a child protection nurse at NHS Bristol, told the Observer: "We have had intelligence that with the credit crunch, cutters are being paid to come over here and do children in a large number as it's cheaper than families taking flights to other countries."

One police source said he had heard of a girl as young as four weeks being subjected to genital mutilation and that there was a desperate desire to get a conviction. Frustration at the lack of action here is compounded by successful prosecutions abroad. The Observer has been told of two older women working as cutters in London.