They show that by the end of this year at least 180 members of the union will have been interviewed by police compared to around 120 every year since 1995.

Kay Jenkins, National Union of Teachers assistant secretary for legal and professional services, blamed the growing “compensation culture” for the increase.

And she told a NUT Cymru conference in Cardiff: “There is now a greater proportion of parents who go straight to the police rather than raising it with the school first and trying to resolve the problem.”

The Association of Chief Police Officers would not comment on the figures, saying it kept no central record of allegations against teachers.

But Ms Jenkins said the case of Marjorie Evans, the Monmouthshire head cleared of slapping a pupil, but who was suspended from her post for more than a year, was just one of many “horror stories” the union was dealing with.

“We ave many more cases - many real horror stories,” said Ms Jenkins. “We have just dealt with a case where four of our members have been suspended from school for three-and-a-half years.

“There are many cases where teachers are completely exonerated but feel that they cannot go back to teaching.

“The gossip and the school-gate committee makes it extremely difficult for teachers to go back to the classroom.”

The figures measure the number of teachers who asked the union to provide them with a solicitor to accompany them to a police station interview.

The numbers had fallen from the early 1990s and stabilised at around 120 a year in 1995.

Ms Jenkins said that there were still too many hasty and lengthy suspensions. She said: “The police do not deal with such cases quickly. They will say it’s not a murder or a serious burglary - all it is is an allegation of a slap or a pull.

“It may be two months after an incident before the pupil is interviewed when there is little chance of a small child having a good recollection of what happened.”