A major union has called for "zero-tolerance" towards assaults on school support staff, as alarming figures emerged from one of the country's largest urban local authorities.
Leaders of the GMB union, which represents teaching assistants and staff such as caretakers, called it a hidden problem that desperately needed to be "brought out in the open".
The union said the figures were shocking and called for urgent action to tackle the problem.
Incidents included biting, kicking, headbutting, chairs being thrown and staff stabbed with pencils.
Union leaders made the comments at the GMB's annual congress recently, as it was revealed pupils had carried out more than 500 attacks on support staff in Bradford in the past 18 months.
The assaults were mainly in primary and special schools, where the majority of the GMB's support staff members are based, but leaders say the figures indicate a wider problem.
The numbers are based on returned incident report forms that are generally submitted to local authorities.
Neil Derrick, GMB senior officer for the Yorkshire region, told the union's annual congress in Southport: "There is a hidden epidemic of violence in our schools which is not being dealt with. The problem appears to be getting worse.
"The lack of any attempt to deal with this problem has also surprised us. The problem is far worse in secondary schools."
GMB national secretary Brian Strutton said the problem was particularly pronounced in special schools. "I was talking to a special school member of staff who had a black eye and she said she got it after being headbutted by a pupil," he said. "I was quite worried when the teacher said 'we get that all the time'.
"We quite rightly now pay a lot of attention to children with special needs, but it doesn't mean support staff are there to be targets of abuse or assault."
The GMB called for councils to publish figures for verbal and physical attacks in every school to show the scale of the problem.
Ray Alderman, a delegate from Bradford, told the conference: "People don't go to work to be attacked - it is totally unacceptable. We want the Government to pressurise local authorities to offer better support to our members and to work to reduce them in the first place."
The union debate comes just months after the Association of Teachers and Lecturers revealed shocking figures on violence against teachers in the classroom.
A survey showed that four in ten teachers had experienced physical aggression, with a quarter saying it was aimed at them. Nearly half the teachers who had dealt with bad behaviour said pupils had used their fists, while four in ten had seen pupils kicking and a handful said they had dealt with incidents in which a child stabbed - or attempted to stab - someone with a knife, pen or pencil.