An exam board had to change 8,000 pupils' marks following the botched launch of a new vocational GCSE last year, it was revealed this week.
The AQA board had to increase the scores of all its candidates for the applied GCSE in information and communication technology after only 0.5 per cent gained a C grade or better on a paper taken last January.
The move, which has cast a shadow over attempts to encourage more pupils to take applied GCSEs, came after the Qualifications and Curriculum Authority launched an investigation into results in the subject.
It found that problems with the mark scheme and with guidance sent to schools and colleges made it virtually impossible for pupils to score higher than 68 per cent on the paper.
As a result, AQA made "scaled adjustments" to the original marks of pupils taking the paper in January 2004, and also those who sat it in June 2003 and June 2004.
All candidates were affected but the board could not say how many improved their original grades as a result.
Even after the changes, results of applied ICT, taken by 41,433 pupils nationally, were much lower than those on traditional courses and the general national vocational qualification. Some schools have since switched to other exams. AQA said the paper had been redesigned for this year's GCSEs.
Its action was revealed in the QCA's annual review and report of the performance of exam boards for 2004.
It reported problems with attempts to guard against pupil cheating, after a van carrying GCSE question papers in four subjects was robbed at knifepoint in south London last May.
Two exam boards replaced around 430,000 papers. However, the report said pupils in some schools had sat the original version.
The QCA had had to check the scripts carefully for any suspicious patterns in pupils' marks but had been satisfied that results had been obtained fairly.
Overall, the report painted a positive picture of the three English boards'
performance. All papers were dispatched on time, it said. Some 2.4 per cent of papers contained errors requiring correction, but schools and colleges were told about almost all of these before the exam started.
There were 3,573 cases of exam or coursework malpractice identified by the three boards last year. The QCA said this was in line with previous years.
Separate QCA reports on whether GCSE and A-levels got easier or harder in biology, chemistry, business studies and economics between 1997-9 and 2003 found no evidence of major changes in difficulty.
GCSE physics had got slightly easier for brighter pupils, but harder for those of lower ability, between 1997 and 2002, the report said.