Girls in the UK are at risk of being forced to undergo female genital mutilation, a High Court judge says.

Mr Justice Keehan says police, social workers, teachers and medics must be aware of warning signs and know how to help.

The judge, who is based in the Family Division of the High Court in London, outlined his thoughts in the foreword to a new book about female genital mutilation (FGM) and the law.

"The practice of female genital mutilation remains widespread across the globe, especially in parts of North Africa, but a substantial number of mutilations are reported to have been undertaken in this jurisdiction," Mr Justice Keehan wrote.

"Accordingly, the risk to girls and young women living in this jurisdiction is not limited to being taken abroad to be subjected to FGM, but includes the risk of having the mutilation performed in this country.

"It is vital in order to prevent FGM that health and social care professionals, local authorities and law enforcement agencies have a clear understanding of the socio-cultural reasons for the practice of FGM, the factors which may indicate a girl or young woman is at real risk of being forced to undergo FGM and of the effective legal steps which can and must be taken."

Barrister Zimran Samuel, a specialist in FGM legislation and author of the book, writes that critics have complained about the law being "ineffective and inadequate" in tackling FGM.

Despite a criminal law being in existence for more than 30 years, and taking a child abroad to perform it being outlawed in 2003, there has never been a successful prosecution of an FGM offence.

But he believes a drive towards greater public awareness and revised legislation offer "strong reasons for optimism".

Two years ago, Mr Samuel said new-style court orders designed to protect girls and women from being subjected to FGM could ''make a very real difference''.

He said protection orders aimed to protect potential victims, rather than punish offenders. Mr Samuel said the orders, which can be imposed by family court judges, could put barriers in front of people who posed a threat and give comfort and support to vulnerable females.

Female Genital Mutilation Law and Practice offers guidance about the protective measures available.