The number of new teachers who fail to find permanent work after completing initial training has more than doubled in just one year, official figures have revealed.
More than half - 52 per cent - of the 33,350 newly qualified teachers who finished training in 2009 had not started their induction years by the end of March 2010.
Last year the figure was just 20 per cent.
The dramatic rise - published by the General Teaching Council for England (GTC) - has prompted worries that too many teachers are being trained and raised the prospect of places being slashed.
There are also concerns that 10,000 unqualified instructors are also now registered with the GTC, adding to competition for jobs.
Newly trained teachers become fully qualified only after completing their induction year.
During that time they have a reduced timetable, receive extra support and further training run by their local authority.
John Howson, teacher recruitment expert and managing director of Education Data Surveys, a sister company of The TES, said: "Is it right that we are training large numbers of people who in the current climate won't go into jobs?
"This is public money being spent on people who might not necessarily go into the public sector.
"It's alarming so many people have not found a permanent job in order to start their induction period. There needs to be a review of how close the relationship between training and the workplace should be - school-based courses have a far higher employment rate."
Professor Howson also questioned whether unqualified instructors are taking jobs which should have gone to NQTs. "The new Government should look very closely at the employment practices of schools," he said. "Instructors should only be taken on when they can't find someone qualified to do the job."
Ian Abbott, associate professor at Warwick University's Institute of Education, said the employment rate seemed "very low".
"We expect significantly more of our students to go on to employment, although it's getting more difficult - it's a competitive market out there," he said.
The figures follow the news that the number of all teachers claiming jobseeker's allowance has risen by 75 per cent to 4,580 in the past two years.
New teachers studying on the job at school-centred initial teacher training courses are more likely to get jobs than those who do a PGCE or other university course.
Last year, 90 per cent of students from 16 school centres entered teaching; only two universities achieved the same figures - Cambridge and Birmingham.
Recent research by Professor Alan Smithers at Buckingham University found employment rates among new teachers were particularly low in modern languages, physics, citizenship, chemistry and religious education. Classics, PE and history had the highest proportions taking up teaching posts.
More newly qualified teachers are going straight into supply work - 14 per cent, up 3 per cent from 2009.
A spokeswoman for the Training and Development Agency for Schools said: "Some NQTs delay going into employment, may not have found a job, or have decided not to pursue a teaching career. Others may be working in a part of the profession where GTC registration is not required such as the independent sector, further or higher education."
NQTS IN INDUCTION THE YEAR AFTER COMPLETING TRAINING*
- 48.4% - 2010
- 79.7% - 2009
- 82% - 2008
- 81.8% - 2007
- 83.3% - 2006
* By the end of March