Teachers’ unions have unanimously backed Chris Keates’ call for the Government to reconsider the law surrounding teachers who have sex with sixth-formers.

Speaking on ITV’s Tonight programme earlier this week, Ms Keates, general secretary of the NASUWT teachers’ union, said sex between teachers and pupils above the age of consent should not be a criminal offence.

Her comments sparked widespread controversy, with many suggesting she thought it was okay for teachers to sleep with their pupils.

At the moment, teachers who have relationships with pupils risk jail or having their name added to the sex-offenders’ register.

But Ms Keates has found support from other heads of teachers unions to get this reviewed.

Philip Parkin, general secretary of Voice, said: “Yes, there is an anomaly in the law that should be addressed. If the law says the age of consent is 16, then it’s 16.”

Mary Bousted, general secretary of the Association of Teachers and Lecturers, agrees that the law is anomalous. “It is wholly unacceptable for a teacher to have a sexual relationship with a pupil with whom they have a relationship of trust,” she said.

“However, there is a legitimate question whether the Government should hold a thorough review of the current law.”

And Christine Blower, acting general secretary for the National Union of Teachers, also called for a review of the existing laws. “We are concerned that there are no grades of penalty in how such matters are dealt with in criminal cases,” she said. The Sexual Offences Act, introduced in 2003, makes it a criminal offence for teachers to have sex with any pupil at their school who is below the age of 18, even if the pupil is above the legal age of consent.

The law is intended to protect vulnerable teenagers from adults who might want to abuse their position of trust.

Ms Keates’ comments about the Act sparked inevitable tabloid outrage. The News of the World claimed that “teachers want right to bed their pupils”. And a reader on the News of the World website added: “teachers are perverts”.

But Ms Keates insists that she has no desire to legitimise classroom affairs. “Where such a relationship occurs, clearly it is a most serious issue,” she said.

“It is grossly unprofessional, and there are disciplinary procedures available to deal with this. The consequence is nearly always dismissal for gross misconduct and being banned from teaching.”

She is echoed by representatives from the other unions: Mr Parkin and Ms Blower insist that teacher-pupil relationships should always be cause for disciplinary action.

Anita Chopra, partner at education-law specialists Match Solicitors, agreed that the effect of such relationships can be profound.

“Obviously, it has implications for students’ education and inability to concentrate in class,” she said. “And it’s a breach of trust and confidence.

“But they are both consenting adults. So for it to be illegal is a bit too strong.”

WHAT THE LAW SAYS:

The legal age of consent is 16. However, adults in a position of trust are not allowed to have sexual relationships with anyone in their care who is under the age of 18, in order to provide additional protection to vulnerable 16-and-17-year-olds.

Under the 2003 Sexual Offences Act, teachers are considered to be in a position of trust with all pupils at their school, regardless of whether or not they teach them. They are therefore not allowed to have sexual relationships with any pupils under the age of 18.

Teachers who are found guilty under this law are liable to imprisonment for up to five years. They will also be added to the sex offenders’ register, which will prevent them from working with children for 10 years.

Teachers who have sexual relationships with 16-or-17-year-olds from another school, by contrast, will not be prosecuted, as they are not considered to occupy a position of trust in relation to these teenagers.