In a dramatic announcement as The TES went to press, Downing Street said Ms Morris was stepping down from the Cabinet after 16 months. In a letter to Prime Minister Tony Blair, who accepted her decision “with regret”, Ms Morris said: “I have not felt I have been as effective as I should be, or as effective as you need me to be.

“I’ve learned what I’m good at, and also what I’m less good at.

“I’m good at dealing with the issues, and in communicating with the teaching profession. I am less good at strategic management of a huge department and I am not good at dealing with the modern media.”

She later said of her job: “If I’m honest I haven’t enjoyed it as much as I did as minister for schools standards. One of the reasons I have not enjoyed it is that it needs a different set of skills.

But she added: “I haven’t lost my enthusiam or ambition for politics or my passion for education.”

Her resignation caught Whitehall by surprise and caps a spectacular fall from grace for Ms Morris who just three months ago was celebrating as education won record spending increases from Chancellor Gordon Brown.

The former teacher has been under intense media scrutiny and the Tories this week turned up the pressure over her failure to keep a pledge to resign if this year’s primary test targets were not met. They were not.

Last October, the newly-promoted Ms Morris denied she ever made the pledge. This week she was forced into a written apology to the House of Commons education select committee.

Barry Sheerman, chairman of the select committee, said: “The media has been very cruel, and she didn’t like that because she is a private person.

“It is a sad day for British politics when a woman of that calibre has been forced out - and she has been forced out by the intense media scrutiny.”

Her resignation was welcomed by shadow education spokesman Damian Green, who said: “Estelle Morris’s failure is the failure of the Government’s education policy. She has lost the confidence of parents and pupils in her ability to run our schools.”

But union leaders mourned her departure. Eamonn O’Kane, general secretary of the National Association of Schoolmasters Union of Women Teachers, described the Tory campaign to remove her as “despicable”.

David Hart, general secretary of the National Association of Head Teachers, said the news was a tragedy for the education service.

TES columnist Professor Ted Wragg was shocked. He said: “We’ve had some prats and some monumental prats doing the job. I would personally prefer to have somebody who manifests some human feelings, makes the odd mistake. You could see she was very unhappy. She was moist-eyed at press conferences.”

Mr Blair said Ms Morris could “leave with a sense of achievement” over moves which would transform the quality of secondary education. He had no doubt she would come back into government.

In recent months though, Ms Morris, 50, had lurched from crisis to crisis. She carried much of the blame for an embarrassing Government U-turn after thousands of pupils were unable to start school at the start of the academic year because of problems surrounding new rules on teachers’

criminal record checks.

It was followed by the A-level grading fiasco which led her to sack Qualifications and Curriculum Authority chairman Sir William Stubbs. He then called on her to resign over the scandal, which resulted in nearly 2,000 students having their papers upgraded. Ms Morris faced further embarrassment after intervening when a Surrey appeals panel re-instated two pupils excluded for making death threats against a teacher though she had no power to do so.

There were also suggestions that she had fallen out with Number 10 and the Treasury over her reported enthusiasm for the restoration of student grants.

The resignation came the day after Ms Morris had presented ground-breaking plans to transform teachers’ working lives, including proposals to recruit thousands more teaching assistants.

The plans were broadly welcomed by teachers’ leaders. But they were at odds with a TES survey of 500 Year 6 teachers earlier this month which revealed most wanted smaller class sizes, rather than more teaching assistants. The poll found 53 per cent of teachers would pass up the chance of an extra pair of hands in favour of fewer pupils in their class. Only four in 10 said a classroom assistant was preferable to a smaller class.

Ministers are planning to give schools the cash to recruit an extra 50,000 support staff from 2001-2006. But the commitment, in their response to the 18-month inquiry into cutting professional workloads, may only amount to an increase of around 20,000 over the next four years, as 30,000 staff were recruited last year.

Teachers are also being offered the prospect of a contractually guaranteed half day a week non-contact time by 2005.

No teacher should be allowed to do more than an hour a week of cover by 2004, and a list of 25 non-teaching tasks will finally be taken off their hands by next September.

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