Teachers say the job is becoming more stressful

Two-thirds of 230 teachers questioned for the National Union of Teachers' survey said indiscipline was preventing them from doing their job.

The union complained of a worsening of pupils' behaviour, while its general secretary, Doug McAvoy, said parents had left a "disciplinary vacuum".

The poll comes as government figures show permanent exclusions have fallen for the first time in three years.

'The flip side'

The Department for Education and Skills found permanent exclusions in England were 9,290 in 2002-3, a decrease of 3% from 9,535 the year before.

John Bangs, the NUT's head of education, said local authorities were putting schools under pressure not to exclude badly behaved pupils, to improve the figures.

He told BBC News Online: "The worsening of behaviour is the flip side of having fewer exclusions.

"We are not calling for more exclusions, but there must be more provision and support for teachers having to deal with badly behaved pupils."

Of the staff questioned for the NUT survey, 155 listed "poor pupil behaviour" as one of the main five barriers to effective teaching.

"Lack of time for discussion and reflection" was cited by 126 and "large class sizes" by 103.

Professors John MacBeath and Maurice Galton of Cambridge University carried out the survey on behalf of the union.

'Frustration'

They then conducted in-depth interviews with 40 teachers.

A lack of parental support was a common complaint.

Teachers also voiced concern over "blanket inclusion" in mainstream schools of children with behavioural problems, which took place "without adequate support and resourcing".

The authors said bad behaviour was creating "frustration", with disciplinary procedures taking up large amounts of time.

Liberal Democrat education spokesman Phil Willis said: "This report confirms that ministers keep ignoring the disastrous effects their policies have on everyday life in our classrooms."