The "shocking" level of physical violence teachers are now facing in schools is caused by a lack of parental discipline and mentally unwell children who "are playing out their distress at school", it has been claimed.
Teachers across UK state schools are being subjected to pupils kicking, punching, spitting and even using weapons in school, according to a survey by the Association of Teachers and Lecturers (ATL).
A survey of education staff suggests that 42.8% have had to deal with violent pupils in the last year, including kicking, punching, spitting and even using weapons in school. Others have faced insults, threats, bullying and harassment, The Press Association reports.
One special needs worker at a Bedfordshire primary school said she had been stabbed in the head with a pencil, while a teacher at a Suffolk secondary academy said they had been "sprayed in the face with deodorant".
In a third case, a support worker at a secondary school in Cheshire said a chair had been thrown that hit her leg.
Dr Mary Bousted, general secretary of ATL, told The Today Programme the level of violence was "shocking" and on the rise.
She said the two main reasons for it were parents failing to discipline kids or give them "clear boundaries at home" and "the number of children coming with mental health problems who are distressed and disturbed and who are playing out their distress at school".
She also warned it was increasingly difficult for children with problems to see a mental health worker.
"That service has really been cut," Dr Bousted said: "There are many children now in schools who are not getting the professional help they need to deal with the issues they have."
Speaking earlier, she said: "Although the majority of pupils are well-behaved and a pleasure to teach, having to deal with challenging or disruptive behaviour is unfortunately par for the course for education staff.
"It is shocking that more than four in 10 education professionals have had to deal with physical violence from a pupil in the last year. No member of staff should be subjected to aggressive behaviour, in any form, while doing their job."
A teaching assistant at a Rochdale primary school claimed: "Staff are regularly verbally abused with very little consequences. Occasionally pupils physically attack members of staff, but this rarely leaders to a day's exclusion."
The survey, which questioned 1,250 education staff at UK state schools last autumn, found that 45.5% think that pupils' behaviour has worsened in the past two years.
Karen Leonard, GMB national lead officer for school support staff, said: "GMB is committed to raising awareness of this issue.
"It is unacceptable to be kicked, punched, spat on or to have school equipment and even furniture thrown at them.
"We have recently launched a national campaign to highlight the problem. "GMB will be challenging schools, academies and local authorities to ensure adequate safeguards are in place to protect our members from such violence."
Of those who said they had faced physical violence, 76.5% said they had experienced pushing and shoving, 37.4% had dealt with punching, 52.4% had faced kicking, 24.1% had dealt with spitting and 2.2% said that pupils had used a weapon, such as a knife.
Around 89.1% of teachers and 90.1% of support workers said they had had to deal with challenging or disruptive behaviour from pupils in the last year. The most common type was verbal abuse - such as insults, threats, swearing, shouting, making accusations and being rude.
Just over half, 52.3%, said they had dealt with bullying - such as pupils isolating a classmate from a friendship group or spreading rumours, while a further 24.2% reported dealing with cyber-bullying and 15.1% had seen homophobic or transphobic bullying.
Nearly one in four, 24.3%, had seen sexual or racial harassment by pupils.
Given a list of reasons for bad behaviour, 84.5% of those polled said that lack of boundaries at home were to blame.
Many suggested that emotional or behavioural problems were responsible, while school staff also thought that relationship breakdown within a family and a lack of positive role models at home were key reasons for poor conduct.
In addition, 64.4% thought that society becoming less respectful to people on front-line jobs was a reason for negative behaviour.
A Department for Education spokesman said: "Teachers and school staff have a right to feel safe while doing their jobs and violence towards them is completely unacceptable.
"We have taken decisive action to put teachers back in charge of the classroom by giving them the powers they need to tackle poor behaviour and discipline.
"We have scrapped 'no touch' rules that stopped teachers removing disruptive pupils from classrooms, and ensured schools' decisions on exclusions can no longer be overruled."