The students fear schools may not employ them or make them work as unqualified teachers which would mean pay cuts of more than pound;5,000.
Lecturers' unions were threatening to escalate action as The TES went to press. Some students fear their studies have been irreversibly damaged by the lack of feedback. It is unclear how many of the 30,000 trainees finishing teaching courses this summer have had studies disrupted by the boycott held by lecturers pressing for pay rises. However, surveys across university departments suggest that between 40 and 60 per cent of students have been affected.
Trainees at universities including Nottingham, Reading, Manchester Metropolitan, Liverpool Hope, Bath Spa, and Chichester were among those complaining that they had "sweat blood and tears" but might be jobless.
Michael Tidd, 27, training at Chichester, hoped to start work this September. "I haven't dared to ask what the school will do if my degree is delayed. Even if they pay me as an unqualified teacher, that will mean earning less than I used to as a library assistant," he said.
Some lecturers have told students that if marks are delayed, schools can employ them as unqualified teachers and give back-pay later. But the Department for Education and Skills has not said it will support this.
A student finishing a three-year primary teaching degree said heads she had met were unaware of the problem and seemed unwilling to employ unqualified teachers. "Primary jobs are already few and far between and I worry that heads will shy away from unqualified new teachers," she said.
Trainees are offered jobs in September on condition of "satisfactory completion" of courses. Training institutions provide the General Teaching Councils of England, Wales and Scotland with names of students who have qualified and award Qualified Teacher Status.
The Association of University Teachers and the college lecturers' union Natfhe -which yesterday merged to form the University and College Union - said that all higher education institutions had been affected. Training institutions which admitted that assignments had not been marked included the biggest in the country, St Martin's college in Lancaster, which trains 1,240 students, and London university's institute of education.
But education departments may have escaped the worst disruption because many staff are Natfhe members. The union encouraged its members to withhold results but, unlike the AUT, suggested they should continue marking.
Some students say they have not received crucial teaching assessments in placement schools and that they will not have time to re-do them if they fail. Allanah Prosten, a PGCE student at Manchester Metropolitan, said she had not received a formal observation since February, and only three of 10 assignments had been marked.
Anna Frank-Keyes, deputy head of primary programmes at the university, said such observations should not have been boycotted.