The advice, which spells out the implications of the Education and Inspections Act introduced earlier this month, outlines a raft of new measures to instil discipline.

Staff can restrain pupils who are harming themselves or others. They can confiscate mobile phones and personal stereos if they are being used against regulations or to harass other pupils. They can also search pupils who are suspected of carrying weapons, although if the pupil is suspected of carrying drugs or stolen goods they should be searched by the police.

Teachers have the power to discipline pupils who have misbehaved off the premises, for example on the walk home, when they are acting as “ambassadors for the school”. In addition, they have the right to keep pupils after school or for Saturday detention and do not have to obtain parents’ permission.

This week delegates at the NUT conference voted to speed up the union’s ability to combat unacceptable pupil behaviour with strike action.

Sue McMahon, from Calderdale, West Yorkshire, said that in the past year her members had been “bitten by a five-year-old, thumped by a six-year-old, kicked by a seven-year-old, spat on by an eight-year-old, punched by a nine-year-old, verbally abused by a 10-year-old, received malicious damage to her car by an 11-year-old, gobbed on by a 12-year-old, told where to go many times by a 13-year-old, headbutted by a 14-year-old and received a facial injury from a 15-year-old so bad that it required hospitalisation”.

The vote will mean lay members, such as Ms McMahon, will now be able to start the process towards industrial action, rather than paid regional officials.

In addition to the disciplinary measures, there are some checks on schools’

power. They should not destroy confiscated equipment or search through text messages without permission. Lunchtime detentions should give pupils time to eat and families can request to change the date of a Saturday detention if there is a good reason, such as a family wedding.

Schools also have a legal duty to tackle bullying and must arrange for a child to be educated if they are excluded for more than six days. The guidance also suggests that children should be praised more than they are punished, at a ratio of 5 to 1. “Praise begins with the frequent use of encouraging language and gestures, both in lessons and around the school,”

explain the notes. Praise could also merit a postcard home or a prize.

Teachers are warned against over-disciplining pupils who may have a “loud”

or over-familiar manner for cultural reasons, and are asked to monitor sanctions by age, ethnicity, gender and special needs. Failure to do so may result in a legal challenge, they are told.

Alan Johnson, the Education Secretary, said: “It’s important that a small minority of young people do not disrupt lessons or undermine the authority of the teacher.”

* Guidance at www.teachernet.gov.uk