NO AMOUNT of revision could have prepared pupils at a Kent grammar school for their GCSE history exam when they were forced to sit the wrong paper.

More than 80 students at Maidstone Grammar School for Girls had been swotting up for questions on crime and punishment in Anglo-Saxon times, but were instead questioned on the role of the church in medieval justice.

The Oxford and Cambridge and RSA exam board (OCR) has accepted full responsibility for the latest exam blunder and the school has been assured that students' grades will not be adversely affected.

Head teacher of the Buckland Road school, Jill Judson, said: "When it arrived the paper actually referred to the period post rather than pre-1066, which was not what they had been told to revise for.

"Obviously it was unnerving for our students and the exam board has admitted it was their error. We complained very strenuously to them and they have told us that none of the students' grades will suffer as a result."

Teachers did not notice the mistake, which applied to history paper two, until after the exam had begun last Wednesday morning, June 19. It was felt that, because the paper involved analysing historical sources which were provided as well as using students' own knowledge, that they could still have a stab at it.

A spokeswoman for the exam board said: "OCR apologises to candidates for the distress and confusion caused when they were faced with questions on a topic area they were not expecting."

"We can assure all candidates that they will not be disadvantaged by this error."

The board's marking scheme will be adjusted to compensate for the mistake.

The school has used OCR for the last four or five years for GCSE exams and this is the first time that there has been a problem with that exam board. The school is not expected to drop OCR because of the blunder, but a final decision will be taken after the mistake has been cleared up.

More than 2,500 candidates, out of a total of 28,500 taking the course nationally, were affected by the error including students at two other secondary schools in the county.

A spokesman from the Qualifications and Curriculum Authority said: "QCA is aware of an error in an OCR GCSE history examination paper and is immediately beginning a formal investigation with OCR."