The General Teaching Council is to begin a review of the probationary period, after disturbing figures reveal that significant numbers of teachers begin their careers in an endless series of isolated and short-term supply jobs.

Although the probe was set up before these findings emerged, they will add urgency to it. A GTC-commissioned analysis by Janet Draper of Moray House showed that 1,000 teachers out of 4,000 who left the profession in 1997-8 were provisionally registered. Of these three-quarters (750) had “no recorded service” which means they had been unable to find teaching jobs.

Scrutiny of a further group of 1,323 probationers found that almost half (529) had been qualified for more than six years, but had been unable to accumulate the continuous two years’ experience necessary to become fully registered teachers.

Ms Draper said some of these figures were higher than she would have expected. She is now trying to secure funding to delve more deeply into the reasons why probation is proving to be such a lengthy experience.

But she and the GTC cautioned against easy conclusions because the issues are complex.

Education authorities facing supply problems hire probationers although they realise it is a less than ideal situation; probationers desperate to get their foot in the door collude.

The Moray House researchers carried out a survey of 92 probationers still on the GTC register who had “no recorded service.” Almost half said they could not find a teaching job; just over two-fifths said they could not wait for a teaching post because of financial commitments; and just under two-fifths said they had found jobs outside teaching.

Others said they had service but had not submitted it, did not want to work in schools, or had no service for personal reasons. Some replied that they were content to continue on supply work and saw no need to complete their probation.

Marie Allan, convener of the GTC’s probation committee, said it may be “a problem that we are never going to solve”. But she expressed concern at the numbers who remain provisionally registered even after several years.

Mary Rose Caden, the council’s convener, said there was also a problem of probationers going into school to take up supply work but failing to reveal they were still on probation.This made it impossible for schools to provide the necessary support, and she called on heads and education authorities to be “vigilant”.

The GTC’s review will look at the needs of all probationers, including improvements to their induction and strengthening the criteria for granting full registration. But the needs of probationers on supply will be a particular focus, Ivor Sutherland, the GTC registrar, said.

Ms Draper commented: “People who start out on a very restricted teaching experience never get the opportunity to develop a full understanding of what it means to have a teaching career, to plan for the future, to be part of a team, to undertake curriculum development.”