Pupils who score the same marks in their English language GCSEs this summer could receive different grades depending on whether they sit their exams in England or Wales, it has emerged.
Leighton Andrews, the Welsh education minister, has decided to break the well-established tradition of agreeing standards with exam regulators in England and Northern Ireland in the wake of last summer's grading crisis.
Mr Andrews ordered a regrade for English language GCSE pupils after the grade boundaries increased between January and June last year amid claims that pupils had missed out on crucial C grades. A similar plea for a regrade was turned down in England by regulator Ofqual, leading to a judicial appeal that ruled in Ofqual's favour last month.
Under plans unveiled by Mr Andrews last week, grade boundaries for English language GCSEs will no longer be agreed between Ofqual and the Welsh government.
The move affects only the WJEC board in Wales, which accounts for 95 per cent of English language entries. No other board's exams are sat by at least 5,000 pupils, the minimum number needed to be included in the new setup.
But WJEC offers English language GCSEs in both England and Wales, meaning pupils could receive the same marks but different final grades.
"GCSE English language is a key qualification," Mr Andrews said. "I am determined that learners in Wales should have confidence that they achieve the grades their work deserves and that other stakeholders should also have confidence that this is the case."
WJEC said it would not have advocated the move, and opposition parties in the Welsh Assembly have criticised the minister.
Gareth Pierce, chief executive of WJEC, said that pupils in Wales should achieve qualifications that have the same currency and portability as their counterparts in the rest of the UK, and that English language was particularly important as a "passport" to employment or further study.
"The special condition in relation to separate papers for candidates in Wales is not one that WJEC would have advocated, but we now need to explore the implications of this with the Welsh government and Ofqual jointly in order to be able to continue to provide assurances regarding comparability of standards," he added.
Angela Burns, the Conservative shadow education minister, said the "ill-advised" announcement risked devaluing Welsh GCSEs. "It is inexplicable why the minister has singled out GCSE English language to create different grade boundaries from examinations set in other parts of the UK," she said. "This unilateral decision could isolate Welsh students and leave them with second-rate qualifications."
But on Twitter last week, Mr Andrews dismissed the concerns as "moaning".
The Welsh government and WJEC have been embroiled in a war of words since last summer's regrading. Earlier this month, when the exam board raised concerns that there could be a repeat of last summer's crisis, it was branded "silly" by the Welsh government.
The exam board has also raised concerns over its future in Wales after the education minister suggested it could be "collapsed into" Qualifications Wales, a proposed new independent regulatory and awarding body.
An Ofqual spokesman said that it would work with colleagues in Wales to "minimise the risk to standards in the summer of 2013 and beyond".
"Our focus, as ever, will be on making sure that appropriate standards are set for candidates of the qualifications we regulate, so that all those who rely on those results know they represent a proper record of their attainment," he added.
"We are considering the implications of the new rules set out by the Welsh government for candidates in Wales."
Making their mark
57.5% - Pass rate in August 2012 for the English language GCSE paper - a fall from 61.6 per cent in 2011.
2,386 - Number of pupils in Wales whose results improved when their English papers were regraded.
1,202 - Number of pupils who had their grades increased from a D to a C.
598 - Number of pupils who had their grades increased from a C to a B.