The London branch of the National Union of Teachers has said the shortage of experienced teachers in parts of the city is at crisis level.

With less than a month before the start of the new term London could be short of 1,000 teachers, which represents almost a quarter of the national shortage.

The problem has been growing steadily as salaries fail to keep pace with the city's soaring costs, especially house prices.

Tim Harrison, from the NUT, said: "Why commute into London when there's jobs available in the area you live.

'Lack of respect'

"It isn't easy to commute and be a teacher because you can't afford, like in many other jobs, to be five minutes late. If the children are in the classroom we've got to be there."

The NUT is calling for London-weighting allowances to be improved.

Nick Padfield, who trained as a teacher but went into IT, said there were many reasons why teaching was not a possibility.

"I found the job almost impossible for several reasons. One, there was a total lack of respect within the classroom environment.

Overseas teachers

"Two, I found myself caught up in so much red tape and bureaucracy that was laid down by Ofsted guidelines and, last of all, the pay was too low."

While the Greater London authority has been pushing for teachers to be offered cheap mortgages, many schools have turned to countries like Australia and South Africa to fill the gap.

But two South African teachers recently advised their fellow countrymen not to come to England, citing unruly pupils and classroom stress.

Eldrid Petersen and Renee Fahrenfort said that England was "getting the children it deserves" and described pupils they had encountered in schools in Hackney in east London as "monsters".