Media playback is unsupported on your device Media caption Education Secretary Michael Gove criticised the decision by the Welsh education minister

Education Secretary Michael Gove has attacked his Welsh counterpart as "irresponsible and mistaken" for ordering disputed GCSEs to be regraded.

Mr Gove has been giving evidence to the education select committee's investigation into head teachers' claims of unfair GCSE grades.

He told MPs that raising Welsh pupils' grades would "undermine confidence" in the value of their qualifications.

The Welsh education minister had said he wanted to resolve an "injustice".

On Tuesday, Labour's Leighton Andrews ordered the WJEC exam board to carry out a regrading of GCSE English exams for pupils who took the exam in Wales.

This is likely to see some students in Wales being moved up from a D grade to a C grade - which is key to allowing them to continue on to A-levels.

'Natural justice'

As Ofqual has refused to change grades in England, it will mean that pupils in England and Wales could have different exam grades for the same marks - which Mr Gove said would weaken the value of GCSEs from Wales in the eyes of employers.

But the Welsh minister hit back at Mr Gove, saying: "It is not our fault that the regulatory system in England is in crisis."

The National Union of Teachers said that Mr Gove had "buried his head in the sand" in refusing to accept the evidence of problems with the exam results.

The awarding of lower grades has been unjust to our pupils and the decision to regrade Welsh pupils and refuse to do the same for candidates in England is a further injustice Patrick Ferguson, Principal, De La Salle Academy, Liverpool

More pupils took the WJEC English paper in England than in Wales - and schools in England have been angered at the prospect of their pupils being put at a disadvantage in this conflict between regulators, politicians and exam boards.

"The awarding of lower grades has been unjust to our pupils and the decision to regrade Welsh pupils and refuse to do the same for candidates in England is a further injustice," said Patrick Ferguson, principal of The De La Salle Academy in Croxteth, Liverpool.

"This could have a life-changing impact upon our students and we are not prepared to stand by and watch it happen."

Pupils at the school who did not get a predicted C grade are being allowed to enter A-levels until the "grade boundary issue is resolved".

Mr Gove rejected suggestions that he should launch an independent inquiry into the disputed grades - but said that individual pupils could appeal against their marks.

The education secretary heard claims that this year's results ran "against natural justice".

But he said that the problems surrounding this year's GCSEs reinforced his view that the qualification needed to be overhauled, that the "modular" structure needed to be replaced and that there were inherent problems with having multiple exam boards competing for the same subjects.

Mr Gove was taken to task by committee chairman Graham Stuart over leaks about changes to the GCSE system which appeared while pupils were still taking the exams.

Mr Stuart had written to the education secretary about this - but Mr Gove's response that leaks were "part of political life" was described as "inadequate" by the committee chairman.

He also said he was "flabbergasted" that Mr Gove did not seem to know the ministerial code's guidance on such leaks.

'Proper part'

In an earlier hearing, head teachers had told the education select committee that many schools have been angered by what they thought had been unfair GCSE English results.

They claimed that in an attempt to compensate for higher grades awarded in January, exam grades were manipulated downwards by Ofqual in the summer - at the expense of individual candidates.

GCSE GRADING ROW 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

Mr Gove told MPs that Ofqual had faced a "difficult decision" but he would not intervene with an independent regulator.

Glenys Stacey, head of Ofqual, told the education select committee on Tuesday that she rejected claims of any unfairness in the results or suggestion of political interference.

"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.

The committee 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.

ENGLISH GCSE In 2010 new GCSE English syllabuses were introduced

These courses involve pupils sitting an exam and submitting two pieces of coursework ("controlled assessment") done under strict classroom supervision

In January 2012 some students completed exams and controlled assessments early

In June 2012 the majority of students completed GCSE English and got their results in August

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.

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.

Shadow education secretary Steven Twigg has called on Mr Gove to make all correspondence between Ofqual and the Department for Education "publicly available at the earliest opportunity".