Teachers have always had the common law power to search pupils, but the Education and Inspections Act 2006 now protects any “person” in any school who seizes pupils’ possessions and retains them.

On top of this, the Violent Crime Reduction Act 2006 has given heads and any authorised member of staff the statutory power to search pupils if they have a reasonable suspicion that one may have in hisher possession a knife or offensive weapon.

If you are carrying out the search, it must be in a private place and you must be the same sex as the pupil and be accompanied by another adult of the same sex as the pupil. This means that a teacher alone in a classroom can ask a pupil to hand over a suspicious item but cannot search them, if refused. The Department for Children, Schools and Families (DCSF) recommends, rather charmingly, that you carry out searches only when judged safe to do so.

You cannot require the pupil to remove any clothing except outer wear, and if you search the pupil’s possessions, you must do this in the presence of another adult.

The person carrying out the search is permitted to use such force as is reasonable in the circumstances for exercising that power, but in this case it is advisable for staff to be trained appropriately.

If a search reveals any “offensive weapons” or knives, or “evidence in relation to an offence”, the school must call in the police. The school has no discretion in this, not even if the head or any other member of staff wanted to resort solely to internal disciplinary procedures.

Remember that the power to search is just that. There is no obligation to do so. The head cannot require staff to conduct the searches, only authorise them to do so - in which case they should be properly trained or experienced. But in the view of the DCSF, the school could engage trained security staff to carry out searches.

Chris Lowe, Trade union adviser and former secondary head.