Schools must do more to warn children about the dangers of forced marriage, the Lords was told today.

Labour spokeswoman Baroness Thornton said there was evidence that schools were doing "very little to ensure pupils are informed about forced marriage and offer them necessary support if they need it".

She added: "In fact there is some evidence that some schools are putting students at risk by contacting family members when children had consulted teachers in confidence."

Lady Thornton was speaking during committee stage debate on the Anti-Social Behaviour, Crime and Policing Bill, which makes forcing someone into a marriage a criminal offence.

The Opposition was calling for front line staff to be given better guidance on how to deal with the problem.

Lady Thornton said the Department for Education did not treat forced marriage as a "child protection issue" in many schools and criminalisation was not enough to tackle forced marriage on its own.

Schools, colleges, police, doctors, social services and airport staff must be aware of what to look for and the appropriate action that needed to be taken.

Action taken was not "uniform or adequate" at present, she said.

Labour former attorney general Baroness Scotland of Asthal agreed that guidance was of "critical importance" if Parliament was to tackle this "most pernicious form of abuse".

Baroness Butler-Sloss, independent crossbench chairman of the National Commission on Forced Marriage, said forced marriage was a major problem.

"We know that a lot of girls and some young men, many of them under 18, are being forced into marriage in Pakistan, Bangladesh, India and other places ...

"It's time that everyone from the Government, through particularly the Department of Education and schools, treated this as a child protection issue," she said.