Nairobi, KENYA: Members of African Gay and Lesbian communities demonstrate against female genital mutilation, 23 January 2007 at the Nairobi World Social Forum venue in Kasarani, Nairobi. Some 46,000 participants are attending the seventh edition of the World Social Forum taking place this week in Kenya, organisers said Monday as hundreds of youths protested registration charges. Organisers had hoped to attract about 160,000 anti-globalisation activists, but about one third of that figure turned up for the conference that kicked off in Nairobi at the weekend and set to conclude on Thursday. AFP PHOTO/MARCO LONGARI (Photo credit should read MARCO LONGARI/AFP/Getty Images)

Nearly 4,000 women and girls have been hospitalized in London for female genital mutilation since 2009, according to figures obtained by the BBC.

The revelations come as Britain grapples with how to halt FGM, which involves removing parts of a women's genitalia for non-medical reasons, according to the World Health Organization. Studies estimate that some 66,000 British women and girls are victims of genital mutilation, according to the Britain's National Society For the Prevention Of Cruelty To Children.

FGM is illegal in the U.K. but no one in the country has been prosecuted for the practice since 1985. Experts note that FGM survivors are often vulnerable young women who may be reluctant to give evidence against older relatives.

London mayor Boris Johnson is backing proposals to crack down on FGM, the BBC reported. "It's time to stop being so nervous, so gingerly and hesitant. This is something that is absolutely intolerable in a place like London," the mayor said.

Campaigner Fahma Mohamed and other students in a rap video slamming FGM, produced by pro-equality charity Integrate Bristol and British newspaper The Guardian.

According to the BBC report, one London hospital treated 795 FGM patients between 2009 and 2013. The hospital said six of them were still under the age of 18, and just eight had been born in the U.K.

The NSPCC notes that FGM is prevalent in at least 28 African countries, as well as parts of the Middle East and Asia. The charity explains that a wide range of social and cultural reasons are given for the practice, including "the mistaken belief it enhances fertility and makes childbirth safer for the infant."

Mohamed, the teen anti-FGM campaigner, is urging Britain to wake up to the prevalence of female genital mutilation in the country and speak out.

"FGM, like all forms of abuse, is everybody's business, regardless of race, gender or religion," she wrote in a recent blog post.