A former government behaviour adviser has described the Coalition's plans to legislate for no-notice detentions as "irresponsible, rude and stupid".
Sir Alan Steer, behaviour "tsar" for the previous Labour administration, has blasted proposals in the Government's Education Bill, now making its way through Parliament, claiming they will create more trouble for teachers, not less.
Currently schools are required to give 24-hours' notice to parents if they want to detain a child for bad behaviour - a measure introduced by the last Conservative government.
But, under the new legislation, ministers are proposing to put in place measures that will enable teachers to keep pupils after school without notifying parents.
Sir Alan, formerly head of Seven Kings High School in Ilford, Essex, said the decision could lead to more serious problems for schools.
"All it needs is one child to have an accident or be molested on their way home from school and then the school will be facing a very difficult situation," he told The TES.
"I have not met anyone who thought that giving notice for a detention was a problem. It is Don Quixote politics - ministers have invented a problem and now they are charging at it.
"I know most schools will think this is stupid. Some teachers or heads may want to keep a student behind, but they would always phone up the parent, just to inform them that their child is being detained, but the amendment to ensure that happens was rejected. It's just lunacy," Sir Alan added.
The former behaviour adviser said his criticisms were not "party political", adding that he backed some of the reforms put forward in the bill, such as the extension of search powers. But he claimed no-notice detentions could leave schools in an "untenable position".
Shadow schools minister Kevin Brennan had tabled an amendment to ensure parents were made aware that their child was being detained, particularly if a child was a carer for a parent or relative, but the amendment was voted down during a bill scrutiny committee last week.
Speaking at the committee, Mr Brennan said: "Where is the great campaign for the removal of the requirement? Where are the people holding up banners saying, '24-hour notice of detention to be abolished now'?
"Was it a measure introduced by a red in tooth and claw, lily-livered, liberal Labour government? No, the current secretary of state for Wales introduced it under a Conservative government in 1996.
"Where has the idea for its removal come from? My charge against the Government is that it is another one of their headline-grabbing initiatives. They dream up such stuff because they know they will get a few headlines in the tabloids," he added.
In response, Graham Stuart, chair of the education select committee, said: "Heads will use the power sensibly and proportionately and come up with their own ways of supporting teachers and communicating with parents sensibly. Suggesting that teachers will all use it in a foolish way and that they necessarily will never communicate with parents is a parody of the truth."
A Department for Education spokesperson added: "We trust teachers to decide whether or not to notify a parent about detentions - we do not feel further legislation is necessary."