Schools have been criticised for wasting the time of the exam body, following an increase of a third in the number of appeals by exam candidates - at an extra cost of more than pound;250,000.

Although the Scottish Qualifications Authority says the rise is mainly the result of its decision to scrap the “derived grades” procedure, the fact that less than half of appeals were successful prompted it to criticise schools and colleges for wasting time and resources.

The appeals process, the SQA pointed out, was intended as a “safety net” for exceptional cases but is now used widely, often without the evidence to support the claims. At Higher, 15 per cent of appeals made last year did not have the necessary evidence.

The authority also criticised “a significant number of centres” that continued to hand in late or incomplete appeals submissions.

A report from the authority stated: “It is noticeable this year that, in some subjects, centres are basing their estimate on what they think the candidate will achieve in the national examination rather than on demonstrated evidence of attainment.”

It continued: “A significant number of centres are still submitting appeals where the evidence is incomplete or missing. In addition, a significant number of centres are making late appeals submissions ... SQA will tighten up on the procedures for late submissions and will no longer chase missing or incomplete evidence, as this is the centre’s responsibility.”

Since the exams crisis in 2000, appeals have been falling as confidence in the system is restored.

But last year, appeals increased by 32.5 per cent, from 45,475 in 2006 to 60,233.

The rise was particularly noticeable at Standard grade and Intermediate 1 where appeals increased by 65.5 and 40.5 per cent respectively on the previous year.

However, a rise had been expected in 2007 following the end of “derived grades”, which triggered an automatic appeal to improve a student’s result where a school had a strong track record of predicting its pupils’ results. Now, students who would have benefited have to submit individual appeals, thereby pushing up the total number.

“People are appealing for around 8 per cent of entries,” said Gill Stewart, depute director of national qualifications at the SQA. “You would expect the number of people who had a bad day on the day of the exam to be lower than that.”

The authority is optimistic that an improved appeals feedback form will help centres with submissions next year. The body also plans to run events to stop centres making appeals that are doomed to fail.

The total direct costs to SQA of appeals in 2007 was pound;830,836, compared with pound;564,643 the previous year.