By Gary Eason BBC News Online education editor

The 2003 exam season has got off to a wobbly start with the revelation that stolen GCSE exam papers had been in circulation - forcing the AQA exam board to reprint some 1.5 million scripts.

Hundreds of thousands will be taking the exams from next week

Changing the exam papers has cost the board an estimated �250,000 - but it stresses that it had no choice because the exams had been compromised by the theft from a Parcelforce delivery van taking scripts to one school.

The papers involved were in English and English literature. In other words, it could hardly have been worse for the board because almost everyone who does GCSEs takes English.

It is not a statutory requirement to take the exams, but studying English is a compulsory part of the national curriculum and anyone who has done the course is officially encouraged to sit the exams.

Last year there were 335,902 entries across the UK for GCSE English and 263,526 for English literature.

Getting the papers the day before is a bit hairy School exams officer Martin Cooper

As the biggest board, AQA (the Assessment and Qualifications Alliance), has the lion's share of the GCSE exams - primarily in England, though some centres in the rest of the UK use its papers.

It reckons half a million students are affected by its having to reprint the papers.

The letter to exam centres - schools and colleges - details which papers are involved.

Its director general, Kathleen Tattersall, says: "I am extremely sorry to have to advise you that the security of all the question papers ... has been compromised."

She adds: "Investigations involving the police, Parcelforce and AQA have now clearly established that copies of these papers have been distributed in the Midlands and, possibly, further afield."

Her letter, written on 9 May, was arriving this week. News organisations were not informed.

The revelations come a day after the exams regulator, the Qualifications and Curriculum Authority (QCA), launched a campaign to reassure A-level students about this year's exam process, following the re-grading fiasco in 2002.

AQA chief Kathleen Tattersall apologised to schools

The authority said it had been kept informed of developments by AQA.

In a statement, it said: "This was a serious theft involving this summer's AQA English language and literature GCSE examination papers. New papers have been printed and will be distributed to the schools in advance of the exams.

"AQA contacted us immediately following the theft. QCA are satisfied that the correct course of action was taken to safeguard the interests of students."

Shortage of examiners

One examinations officer, Martin Cooper at Queen Elizabeth's School in Wimborne, Dorset, said he had the whole of Year 11, about 350 students, taking the English exam "and getting the papers the day before is a bit hairy".

"We cross our fingers and hope," he said.

"As this is a national thing I would hope they would reschedule the whole examination if they get into problems."

Mr Cooper said he was not unduly alarmed about the incident, which was plainly a one-off outside the control of the exam board.

But he and his colleagues had underlying concerns about the shortage of exam markers.

Normally, he said, scripts came to the schools with pre-addressed envelopes so that, once sat, they could be sent directly to examiners' homes to be marked.

"A lot of the address labels are just going back to the exam boards this year - from all the boards - which suggests they are struggling a bit to find people to do the marking."

Also, the deadline for returning coursework this year was much shorter than usual at both GCSE and A-level.

He added: "I don't think we have had any alarm bells ringing about them not being able to cope yet but the whole thing is getting very, very tight, the exam system these days."

The head of the QCA himself, Ken Boston, has questioned the value of having GCSEs at the end of compulsory education, when so many now stay on to take A-levels.

He also said exam marking was "a cottage industry" run by "moonlighters" on piece work.

Day-long centres in which specialist markers dealt with parts of scripts would be much more efficient, Dr Boston said last year.