Poorly behaved pupils and too much work have been blamed for a 30 per cent increase in the number of teachers quitting Birmingham schools over the last four years.

Bad management and an unhealthy work/life balance were also identified as reasons for more than 1,700 teachers leaving city schools between 2002 and 2005.

The figure represents nearly 70 per cent of all leavers and compares with only 447 who departed due to retirement.

The shock findings are highlighted in a survey of teachers conducted by Birmingham City Council.

The report, entitled Recruitment, Support and Retention of Teachers, also contains feedback of an exit questionnaire that provides a disturbing insight into the pressures faced by Birmingham teachers.

One 26-year-old newly qualified male teacher leaving the authority to teach elsewhere wrote: "I was constantly verbally abused by pupils, physical behaviour of students was out of control and there was little senior management could do about this.

"I, like 20 to 30 other members of staff, wanted out."

Another 57-year-old female primary school teacher who took early retirement claimed to have developed an ulcer and shingles due to stress.

She wrote: "During the last five years I feel that teachers have been under increasing pressure to 'perform'."

She claimed the pressure of new initiatives meant "much of the joy and spontaneity in teaching has disappeared with the overload of planning and paperwork".

"I could not face another three years, much as I love teaching."

The city council is in the process of developing a recruitment and retention strategy for schools. The report also called for closer monitoring of long term trends in teacher retention, particularly in light of a looming retirement "timebomb" with many of the city's 10,000 teachers nearing the end of their working life.

Birmingham's elected head of education Councillor Les Lawrence (Con Northfield) called for schools to adopt a "zero tolerance" to poor discipline to protect teachers.

"We have got to get back where people know the boundaries of behaviour and understand the concept of responsibility to themselves, others and the community," he said.

He also criticised the behaviour of parents who felt they had a right to behave abusively towards teachers outside school gates.

"It is a significant minority but it does have an effect on the desire of some teachers to continue," he said.

"Any parent who behaves in a way that is considered as threatening verbal abuse or physical abuse should be subject to the full force of the law."

Coun Lawrence claimed workforce reforms giving teachers ten per cent non-contact time and more support staff will help improve retention.

But he warned the "very prescribed environment" of the curriculum in primary schools continued to be a problem.

"It is important the Government realises that if you really want teachers to teach you should trust their professional judgement rather than prescribing what they teach," he added.

Nigel Baker, deputy general secretary of the National Union of Teachers' Birmingham branch, blamed poor management and an uninspiring curriculum for staff retention problems.