More than 20,000 girls under 15 in England and Wales could be at risk of genital mutilation, a charity warns.
Female circumcision is deeply rooted in many societies
Forward, which campaigns against the practice, says health workers and local officials should do more to stop it.
The charity says its estimate of 20,000 girls at risk is conservative because many women are too ashamed or afraid to talk about their experiences.
Female genital mutilation is seen in some communities as an initiation into adulthood for young girls.
Forward founder Efua Dorkenoo said the government had introduced a law against the practice, as part of its child protection policies, which had to be applied at local level.
"We expect that on the ground at local authority level, the health professionals and the schools would be alert to it so they would actually mainstream the prevention into what they do," she said.
Female genital mutilation is practised in a number of mainly Muslim African communities, and the tradition can travel when immigrants settle abroad.
The practice is believed to reduce a woman's desire for sex, and therefore sex outside marriage, and can be carried out on girls as young as four.
The practice has no basis in religion and the victims can face a lifetime of physical or psychological problems.
In some cases the mutilation is carried out here. In others the children are taken to their families' countries in Africa or the Middle East.