Women who fear forced marriages hide a spoon in their underwear so they can flee from their parents at airport security when they are taken aside to be searched

Karma Nirvana, a Derby-based campaign group which supports victims of forced marriage, advises girls to use a spoon, or any other metal object, to set off detectors at the airport and separate themselves from parents.

The charity says a number of girls have used the tactic to avoid being taken overseas and entered into a life of servitude.

Last week, the Government warned that thousands of schoolgirls are at risk of being sent away to enter into forced marriages during the summer holidays.

The Foreign Office's Forced Marriage Unit gave support for 1,485 cases up to December 2012, although it is feared many more go unreported. Around 400 of these were reported int he three months up to the end of August.

More than a third were under the age of 17 and more than 80 per cent were female.

Speaking to the AFP news agency, Natasha Rattu, Karma Nirvana's operations manager, said that when worried youngsters ring the charity's helpline, 'if they don't know exactly when it may happen or if it's going to happen, we advise them to put a spoon in their underwear.

'When they go through security, it will highlight this object in a private area and, if 16 or over, they will be taken to a safe space where they have that one last opportunity to disclose they're being forced to marry.'

Doctors, teachers and airport staff are among those being asked to remain vigilant to the possibility of young girls being taken away during the summer break.

Of the cases that the FMU handles, almost half relate to forced marriages in Pakistan. Other countries where girls are sent include Bangladesh, India, Somalia, Turkey, Iraq and Iran.

The oldest case was a woman aged 71 and the youngest just two-years-old.

A victim, whose identity was protected by Essex Police, told AFP that her father forced her into a marriage in India, after threatening to find her and kill her if she tried to run away.

'I was shipped off with a total stranger. That night I was raped by my husband and this abuse continued for about eight and half years of my life,' she said. She later escaped.