Schools have been entering pupils for GCSE maths with multiple exam boards in a "frightening" bid to achieve higher grades and improve league table rankings, a senior exam board official who led the government's curriculum review has warned.
The practice has developed around modular exams, where assessment is broken into chunks during courses. Pupils take initial modules with more than one board, then continue with the one with which they score highest, according to Tim Oates, director of research at Cambridge Assessment, which owns the OCR board.
Mr Oates revealed his "deep misgivings" about the practice after TES revealed last month that hundreds of secondaries have been entering pupils for GCSE and IGCSE English exams in a bid to gain higher grades.
Mr Oates said he had examined evidence that showed pupils were being entered for initial modules in maths with multiple boards.
"In my view, and I come from an exam board, it is an entirely illegitimate use of public funding in relationship to education. It is wasted money. I'd much rather see those exam fees being spent on high-quality learning resources."
Later, he told TES: "There has to be a question mark over the cost of this practice and whether it is simply being driven by accountability arrangements - the CD borderline."
Mr Oates said he could not provide specific figures as they were confidential.
His comments come as the exam system is being revamped, with plans to replace GCSEs with more traditional English Baccalaureate Certificates in English, maths and science. The plan is that these qualifications would each be assessed by a single board.
Ministers have also scrapped modular GCSEs, with courses that started in September 2012 being assessed with end-of-course exams in 2014. This should put an end to the practice identified by Mr Oates, although modular courses still exist at A level.
Russell Hobby, general secretary of heads' union the NAHT, said: "These schools are doing the best they can within a bad system. If you don't want people to do something, you shouldn't reward them for doing it and punish them for not doing it. It is not as simple as modular exams bad, linear exams good. They are different and each has pros and cons.
"There is an extent, though, to which the profession can be too complicit with incentives. At some point you have to say, this is no longer in the interest of the child. But the danger is, as stakes get ever higher, that professional integrity is being corroded."