UNION leaders are calling for a single national examination board after 140 A-Level papers were sent to the wrong address for marking.

In the latest in a series of blunders by exam boards, the scripts were delivered to the home of Marc Patterson in Pittington, County Durham.

The package had been posted for marking and was addressed to a Mr Lanning, an examiner who used to live in Pittington.

Mr Patterson, 26, said it was two weeks before the Assessment and Qualifications Alliance (AQA) collected them after he had called the Manchester exam board three times to tell them of the error.

Last night, Hans Ruyssenaars, the National Association of Schoolmasters Union of Women Teachers' (NASUWT) national executive member for Cleveland, condemned the mistake.

"It's quite appalling, both for the young people who have worked so hard and the teachers who have been slogging their guts out to make sure things have gone smoothly," he said.

"We have a national curriculum, a national education system and it is time we started looking at the whole business of exam boards."

A single exam board would provide something which was "publicly answerable", he said.

Yesterday, George Turnbull, of the AQA, said the information technology papers had been collected immediately the board realised they had been sent to the wrong place. They would be marked in time to be released with A- Level results next Thursday.

He said: ''It seems the address wasn't as accurate as it should be. Whether that was the examiner not informing us of a change of address is something we will look into.

''These things happen in any organisation of this size from time to time. We apologise for any inconvenience caused."

AQA is one of the three main exam boards in England, the others are Edexcel and OCR.

Edexcel has been criticised this year for a series of mishaps involving its exams.

Earlier this year, David Dunn, headteacher of the independent Yarm School, near Stockton, highlighted a printing mistake which made a nonsense of a question in a maths paper sat by Edexcel.

Students in Darlington also found that their Key Skills level three papers contained missing and duplicate questions.

But the boards have hit back, saying that with millions more entries to process following the introduction of AS-Levels in 2000, occasional mistakes are inevitable.