Monmouth MP David Davies has called for a change to Welsh Government guidance after a school failed to involve police when a teacher was knocked unconscious.
History teacher Jane Breeze was taken to hospital on Friday with head injuries after a pupil dropped a full can of Coke from four storeys up at Croesyceiliog School.
She is now recovering at home in Abergavenny.
Mr Davies contacted Gwent Police and Crime Commissioner Ian Johnston after hearing that the incident would not be investigated by the police. Instead, the police were told it would be dealt with under the School Crime Beat Protocol.
Backed by the Welsh Government, the aim of the protocol is to avoid “criminalising” young people.
“The victim was visited in hospital on Friday morning by a senior member of staff and told that the police had been informed,” said Mr Davies.
“She assumed that a police investigation would be taking place. In fact the police have told me that although they were informed about the incident, they were told it would be dealt with under the School Crime Beat Protocol.
“This is a set of Welsh Assembly regulations which were drawn up to stop the police from being called to make arrests every time a minor incident happens in a school.
“This was not a minor incident. The teacher could easily have been killed or left paralysed and she is still unwell and receiving medical care. I am astonished that someone though it would be appropriate to keep the police away and try to deal with it within the school.”
Mr Davies believes there will be “natural concern” if the School Crime Beat Protocol is being used to “cover-up” serious incidents in schools.
“After being contacted by the victim’s family, I rang the Gwent Police and Crime Commissioner who was superb and has instigated a full investigation,” he said.
“I am now trying to establish whether the failure to act immediately was as a result of the Welsh Assembly guidelines or a failure to understand them by Torfaen Local Education Authority.
“Teachers should have the right to safely go about their business without fear of receiving serious injuries, and they should be able to rely on their management to back them if they are attacked.”