Classrooms could become "battlefields" unless teachers are given greater support, the Government has been warned.
Birmingham teacher Maria Hesson spoke out against unruly behaviour as it was revealed one in seven teachers had been attacked by a pupil.
Her warning came as she addressed thousands of teachers at the Birmingham-based NASUWT union’s annual conference in Bournemouth.
The results of a survey released to coincide with the conference found more than one in five teachers had been threatened by their students – with one in seven suffering actual violence.
About 12,000 teachers from across the UK responded to the questionnaire, which also found 85 per cent of teachers had been subjected to verbal abuse by a pupil in the past year.
More than a third of those questioned said they had also experienced abuse from a parent or carer.
Ms Hesson, who was among 1,000 Birmingham teachers at the conference, said: “Threatening the teacher with assault and violence, invading our personal space, smoking out of the window during lessons, pupils who take advantage of teachers who they perceived to be powerless.
“Teachers in some schools are having to spend too much time disciplining the unruly instead of teaching.
“If the Government fails to support teachers, classrooms will become battlegrounds and teaching and learning will suffer.”
Those who responded to the questionnaire said a lack of parental support, pupils not coming to school ready to learn and the low aspirations of families and students were the biggest causes of discipline problems in schools.
The survey also found there was a “continuing problem” of low-level disruption in the classroom, with teachers citing chatter in lessons, students failing to complete work and not following rules as the biggest behaviour problems on a day-to-day basis.
The NASUWT said the survey results “reinforced the concerns” of teachers about pupil behaviour.
It claimed cuts to education were “seriously undermining” schools’ ability to maintain discipline.
NASUWT general secretary Chris Keates said: “This survey shows teachers are working hard to maintain high standards of behaviour, but in too many cases are not being supported appropriately. It is a sad indictment that almost half of teachers feel they are not supported in maintaining discipline by school management.
“Teachers need to be backed by school management but regrettably, too many school leaders have not taught for years and have lost touch with the realities of the classroom.
“When the NASUWT is called in to support teachers, all too often we find that there is more monitoring and surveillance of the behaviour of teachers than of the pupils.”
Two years ago, it emerged that 150 pupils a day were being sent home for bad behaviour in West Midland schools.
Government data revealed 578 children were expelled and more than 28,000 were suspended from the region’s classrooms during the 2009-10 school year.
Reasons for exclusions included physical or verbal abuse towards teachers and fellow classmates, bullying and drink and drugs.
A total of 201 children were expelled from school over the course of the year.
That figure included 102 for physical or verbal abuse towards teachers or fellow students, 64 for “persistent disruptive behaviour” and nine for reasons relating to drugs and alcohol.