The head of the examinations watchdog says he has been unfairly dismissed by the Education Secretary, Estelle Morris.

Sir William Stubbs was sacked from his job at the Qualifications and Curriculum Authority (QCA), an hour after an independent inquiry cleared both him and Estelle Morris of any wrongdoing in the crisis over A-level results.

She insisted he had to go because he had lost the trust of the exam boards and schools.

I'm a free man, found innocent, and yet the subject of unfair dismissal

Sir William Stubbs

Sir William said he had been put under "enormous pressure" to resign.

"She felt that my departure was necessary in order to remove drift and uncertainty in the education service, I think were her words."

But he insisted he been "wholly exonerated" by Mike Tomlinson, the former chief inspector of schools watchdog Ofsted who had carried out the inquiry.

Sir William added: "I was put under enormous pressure by the secretary of state to consider my position and she said if I went quietly and reasonably she would speak kindly of me recognising what I had done for education over many years.

"And that I should draw my own conclusion if I didn't. I reflected on that and I wrote her a letter."

Mike Tomlinson: Denied report was "a whitewash"

Speaking on the BBC's Newsnight programme, schools minister David Miliband defended the action taken over Sir William.

"The review makes it clear that everyone has to take responsibility for certain aspects of the affair," he said.

The independent inquiry has recommended that exam papers in about 12 A-level subjects be re-graded, potentially affecting thousands of students.

But pupils will have to wait until Tuesday to find out exactly which papers are involved and may have been unfairly marked down.

No grades will be reduced.

Mr Tomlinson said flaws in the new A-level system were partly responsible for what was "an accident waiting to happen".

He spent a week gathering evidence and interviewing key players but cleared all concerned of acting improperly.

The exam boards - Oxford and Cambridge and RSA (OCR), the Assessment and Qualifications Alliance (AQA) and Edexcel - did not breach the code of practice governing examinations, he said.

Estelle Morris has resisted resignation calls

But he said Sir William had acted in a way that was perceived by the exam boards as putting pressure on them to "get tough" to keep grades in line with last year's results.

"There is no doubt in my mind that the heads of exam boards felt under pressure to maintain standards."

But he made clear that the QCA chief had not acted improperly in urging them to prevent "grade drift".

"What he said and what he wrote was clearly within the regulatory guidelines," Mr Tomlinson said.

He also made clear that no blame was being levelled at schools themselves.

It was the sheer complexity of the AS-level and A-level system that had created an environment of confusion.

Resignation call

The findings of the inquiry were criticised by Chris Woodhead, a former chief inspector of schools.

Mr Woodhead, an outspoken critic of government education policy, said it was "depressingly inevitable" that the inquiry would exonerate all involved.

Thousands of students have been denied a university place

Mandy Telford, National Union of Students

Ms Morris accepted responsibility for the fact that the A-level reforms were introduced too quickly, and offered students involved an apology.

But she rejected Conservative calls for her to resign, saying she was "proud" to have been part of a Labour Government that broadened the sixth form curriculum.

Fundamentally flawed

David Hart, of the National Association of Head Teachers, said he believed the A-level system was so fundamentally flawed it would have to be scrapped.

"I think in the long-term it is finished," he said.

But Mr Miliband said talk of getting rid of A-levels was "premature".

"It is completely wrong to say that people in the department or myself believe that we should head off in a completely different direction," the schools minister told Newsnight.

Ann-Marie Ellis, 18, who sat English Literature at Wrekin College, in Wellington, Shropshire, saw her final grade drop from an A to a B when she was given a U-grade in her final exam - despite straight As in her five previous papers on the subject.

She said of the report: "It's just too little too late. This should never have happened in the first place. It was very unfair."