Academics have rejected scores of candidates hoping to enrol on the new fast-track teacher training scheme because they fear the ex-bankers and other former financial high-flyers are not up to the job.
Those running the first of the courses - which reduce the time to qualify to six months - only need to find 40 trainees by this September. But they are concerned they may not even get that many because most of the applicants require far more training before they can be let loose in the classroom.
The intensive route to qualified teacher status (QTS) for "talented career switchers" is the invention of Gordon Brown, who said that it would "make a huge difference to the profession".
Those on the pilot course, run by the Institute of Education in London, will be sent into schools after just a 10-day induction period.
Dylan Wiliam, deputy director of the IoE, is concerned that many will need longer to qualify.
"The course has attracted a lot of interest so far but we feel very few will reach QTS in six months - they won't reach the standard in that time," he said.
"If they can't reach this hurdle to entry we are directing them towards longer courses. We want to take 40 students, but if we can't get 40 of the best people we will leave empty places.
"So far we have been only accepting those with excellent personality and communication skills."
Professor Wiliam said the IoE regarded the training as an "experiment" and chose to be involved as it saw it as a useful research project.
"We wouldn't have bid for this if it wasn't going to be a pilot scheme and evaluated by the TDA (Training and Development Agency for Schools) regularly," he said.
The course will start in September and finish at Easter. But because there will be few jobs available then the students are likely to continue working in their training placement schools until the end of summer.
Even though they will be in the classroom in mid-September, school placements for all the fast-track trainees have not been agreed yet.
Professor Wiliam said there had been a mixed reaction from potential placement schools.
"Obviously, some schools have made plans for September already but others really quite like having students because they can get a good look at them before they decide whether or not to offer them a job," he said.
Details of the course were only released following a question in the House of Lords by Conservative peer Pauline Perry.
Baroness Perry said the course had "caused a great deal of anxiety" among academics.
"They feel it will be of a lower standard than the current courses of 12 months and that this will create inequalities between those who have trained on the full 12-month course and those who have had only half that training," she said.
Delyth Morgan, junior minister for children, downplayed the concerns.
"We are talking about a small pilot delivered by an extremely expert institution, which will be rigorously evaluated," she said. "It is not about any reduction in quality."
John Bangs, head of education for the NUT, said he was concerned that putting trainees into schools after 10 days would create a burden for the teachers who worked with them.
- Trainees will get 10 days' university-based induction before entering the classroom. This is far shorter than for PGCE students, who normally get about 10 weeks, and those on Teach First, who get a six-week residential course. Even those on the Graduate Teacher Programme and School Centred Initial Teacher Training scheme can receive up to a month's initial induction.
- The fast-track programme will last 120 days, about 60 of which will be spent at the institute and 60 in schools.
- Students will be in classrooms four days a week, which includes one day training in school; the fifth day will be at the institute.