Education Secretary Michael Gove has refused to intervene in the row over GCSE English grades, despite admitting pupils have been treated unfairly.
At departmental questions in the Commons on 3 September 2012, he told MPs it was up to England's exams regulator Ofqual to uphold standards and oversee marking and grades.
Schools have threatened legal action after grade boundaries were moved dramatically part way through the year.
Labour's Stephen Twigg said it was "rough justice".
Mr Gove had been called to explain to MPs exactly what happened in this year's exams sat by pupils in England, Wales and Northern Ireland.
But he told the Commons it was not his place to get involved with decisions about marking and exam grades.
In response to a question from shadow education secretary Mr Twigg, he said: "If ministers were to interfere in Ofqual's decisions they would be meddling where they should not interfere."
It was the examinations themselves that were at fault and needed to change, he stressed.
But Mr Twigg said it was "rough justice" that young people were getting a D grade in the summer that would have got a C grade if it had been submitted in January.