By Sean Coughlan BBC News Online education staff

Suspicions of a security breach have prompted an exam board to change a GCSE paper due to be taken next month.

The OCR exam board has withdrawn the original version of an English GCSE paper, after they found that some pupils appeared to "know too much" about the exam's contents.

The exam board is investigating information passed to it about security fears

The board says that information has been passed to them which has been serious enough to prompt the decision to issue a different version the exam paper - which will be taken by over 40,000 pupils on June 5.

Although fears of cheating are so far unproven, the OCR board was suspicious of what some pupils seemed to know in advance of taking the exam.

They have declined to give details of whether the information came from pupils, teachers, parents or exam officials, but the board says that it has needed to act swiftly to "ensure the integrity of the examination".

So far the police are not involved in the inquiry, but the board says it is carrying out its own investigation.

'Extremely serious'

"Any actual or suspected breach of security can disadvantage candidates taking exams, which is why we take such matters extremely seriously," said an OCR spokesperson.

"Even where there is not conclusive evidence that the questions are known, we believe it to be in the interests of all candidates to replace the paper."

The exam paper, GCSE English 1500/3, looked at non-fiction media texts. In order to distinguish the re-sent paper from the original, the replacement will be printed on blue paper.

Last week, the AQA exam board had to re-print English GCSE papers for half a million students, after exam papers were stolen in a van theft.

There were fears that the theft of the van carrying the papers would compromise the security of the exam.