Some were threatened by pupils brandishing weapons, and others by parents, according to the research from the University of Leicester.

While most teachers said they were not concerned about being attacked, nearly one in five said they were worried.

Teachers were more fearful of having something stolen from them at school, with 48% expressing concern.

The survey was conducted by a group called Perpetuity, a spin-out from the University of Leicester, and sponsored by security specialists TAC UK.

Criminologist Professor Martin Gill, who led the research team, said: "There was an overall perception of safety and security among most staff.

"But some feel unsafe, and most teachers were victimised in some way, some seriously. As they stated in their responses, this can impact negatively on the whole learning experience."

Two-thirds - 66% - of the teachers reported that they had been verbally or physically assaulted by pupils in the past year.

The study found that 21% of teachers said they had been verbally or physically assaulted by a parent or guardian in the last year and 6% by an intruder at the school.

The survey questioned 300 teachers and conducted follow-up interviews with other education experts. The study followed Government figures showing a sharp rise last year in the number of times teenagers were suspended for disrupting lessons, verbal abuse and assaulting teachers and other pupils.