Board was told maths exam had a misprint

Exam board officials knew five hours before a maths exam was taken that a misprint on the paper would leave students facing an unsolvable question, it emerged last night.

Pressure is now mounting on Britain's second largest exam board to allow 2,500 sixth formers to retake the AS-level.

The mistake was spotted first at a school in Hong Kong, where students sat the exam ­ devised by the Edexcel exam board ­ eight hours ahead of schools in Britain.

The school alerted the board by an e-mail that arrived sometime after 8am in London. The exam was to be taken in 300 schools and colleges in England, Wales and Northern Ireland at 1.30pm that afternoon.

However, the decision was taken not to inform schools, meaning sixth formers across the world may have taken the flawed exam and want to retake it. The company says it supplies more than 100 countries with examinations, although it is not clear how many took the affected paper.

John Dunford, general secretary of the Secondary Heads' Association, demanded that all pupils be allowed to resit the exam or for the marks from the flawed paperto be cancelled.

Paul Sokoloff, Edexcel's qualifications director, admitted the blunder was "a dreadful state of affairs" but insisted that calls for every student to retake it would be an overreaction.

The flawed question involved two diagrams, one in thequestion paper and another in students' answer booklet.

The two diagrams should have been identical but one had been printed incorrectly.

The question was only worth 3 per cent of a complete maths AS-level but at least two students who sat the exam claim the mistake left them so unsettled that they performed badly in the rest of the paper and fear it could cost them their university places. Another school suspended the exam session when the mistake was spotted.

Edexcel was facing the prospect of losing its multi-million pound contract to run GCSEs, AS-levels and A-levels after the latest in a long line of embarrassing blunders.

Estelle Morris, the Secretary of State for Education, was said to be "absolutely seething" over the complaint.

The Qualifications and Curriculum Authority, which is responsible for awarding contracts to examination boards, ordered Edexcel to produce a preliminary report on what went wrong with the paper by yesterday evening.

The paper, decision maths, was taken in about 300 schools in England, Wales and Northern Ireland.

David Dunn, headteacher of Yarm School, near Stockton-on-Tees, who suspended the exam when the mistake was discovered, said he would settle for nothing less than for his students to have the opportunity to retake the exam.

Mr Sokoloff said: "There are mechanisms in place to ensure the absolute minimum disadvantage occurs to the students."

In another development, a Kent college said the exam board had failed to send two pages of a multiple-choice key skills exam in communications and information technology.

Edexcel has been forced to send pages by fax and courier, compromising the usual security arrangements for exams.