11 September 2012 Last updated at 12:53 ET By Sean Coughlan BBC News education correspondent 
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Welsh Education Minister Leighton Andrews: Pupils "need to know where they stand"
Pupils in England who took the disputed GCSE English exam could end up with a lower grade for exactly the same work as their counterparts in Wales.
This follows an order from the Welsh government to regrade GCSEs in Wales.
The WJEC exam board says it is being told to raise GCSE grades in Wales while keeping them down in England.
The exam board says it wants conflicting regulators, Ofqual and the Welsh government, to find a more "coherent and rational way forward".
Head teachers earlier told the education select committee that many schools had been angered by what they thought had been unfair GCSE English results.
But Glenys Stacey, head of Ofqual, told the education select committee that she rejected claims of any unfair manipulation of results or suggestion of political interference.
'Difficult and unexpected' "We played our proper part," she told the investigation into this summer's controversial GCSE exam grades - and ruled out any further change in grades in England.
But the Welsh exam board, WJEC, has been ordered by the education minister in Wales to regrade the results in the disputed English exam - a requirement that would only apply to pupils in exam centres in Wales.
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- Issues with GCSE English grading emerged as results reached schools last month
- Heads suggested the exams had been marked over-harshly after Ofqual told exam boards to keep an eye on grade inflation
- Exam boards told reporters grade boundaries had changed significantly mid-way through the year
- Alterations were as much as 10 marks
- Heads complained pupils who sat GCSE English in the winter might have got a lower mark had they sat it in the summer
- Their unions called for an investigation and some mentioned legal action
- Ofqual held a short inquiry but refused to order regrading
Welsh Education Minister Leighton Andrews said on Tuesday that pupils should not have to "live with the consequences of having been awarded what, in all likelihood, is the wrong GCSE grade" - and promised "swift resolution of injustice".
This places the exam board - which has more candidates in England than Wales - in what it calls a "difficult and unexpected position".
"We now find one regulator confirming that the decision made was correct, and another asking us to re-grade, reversing the previous joint decision," says a spokesman for the WJEC exam board - which is believed to be the second biggest provider in the UK for this exam.
This would mean that within the common currency of the GCSE, there could be different levels of awards for the same piece of work from the same exam board, depending on whether the exam was taken in Wales or England.
The select committee had also been told by Ofqual that there had been concerns that pupils in Wales were performing at a lower level than in England - and that this had caused difficulties in setting grades with the WJEC exam board.
This confusion over the value of GCSEs comes against a background in which Education Secretary Michael Gove is preparing to overhaul the GCSE system for pupils in England.
'Major flaws' On Tuesday morning, MPs on the education select committee had heard accusations from head teachers' leader Brian Lightman that there had been "major flaws" in this year's GCSE English grades.
Mike Griffiths, head of Northampton School for Boys, told the select committee that the unreliability of the results in his school showed that "Ofqual failed to maintain standards".
Pupils who were given a D grade rather than the expected C grade could mean that difference between staying on at school or dropping out and becoming a Neet, said Kenny Fredericks, head of George Green's School in east London.
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Brian Lightman: "Implementation of new examination was deeply flawed"
Mr Lightman, leader of the Association of School and College Leaders, told MPs that he believed that the exam grades for pupils taking the English GCSE in the summer had been been forced downwards in an attempt to balance an "over-generous" marking in January - in a way that was unfair for individual students.
But Ms Stacey defended Ofqual's role in ensuring that the grades awarded for exams accurately reflected the level of achievement.
She said there had been many "significant unknowns" in changes to modules of the GCSE English exam, which had to be resolved in the final awarding of grades.
Ofqual says that the June grade boundaries were set at the right level, but has acknowledged there was a problem with the January boundaries - and it has continued to refuse to order exam boards to regrade this year's exams.
Before the committee took evidence, the Times Educational Supplement published letters revealing the pressure put on one of England's largest exam boards, Edexcel to change its grade boundaries - in a way that prevented a rise in grades.
Ms Stacey told the select committee that if the exam board had not complied, she would have used her powers to force them to change the grades.
