David Blunkett declared today that he had no intention of resigning from the Cabinet, even as the Tories accused him of a third breach of a ministerial code of conduct.

The latest breach involved paid work for an international educational charity during Mr Blunkett's enforced absence from Government - work that was declared to parliamentary authorities, but was not discussed with the independent committee governing the employment of ex-ministers.

Although it appeared to be less damaging than a decision to serve as a director of a DNA-testing company, the latest accusation led to renewed accusations that Tony Blair was failing to enforce the code on his ministers. Chris Grayling, the Shadow Leader of the Commons, said: "I am astonished that Mr Blunkett has broken the Ministerial Code on yet another occasion. This is getting beyond a joke."

Mr Blunkett, the Work and Pensions Secretary, told the Sheffield Star today that he had done nothing wrong. "The pressure is not continuing," he said. "The Prime Minister has made his decision and no matter what the Conservative Party want, I am not resigning."

He added: "This is a straight political battle with the Conservative Party and their allies in the media, and decency. I have done nothing wrong at any stage. I have been transparent about everything I have done. "

The Times revealed today that between December and March Mr Blunkett received three letters from the independent Advisory Committee on Business Appointments, which advises ministers on their paid work when they leave public office.

The letters warned him of his responsibilities as a former minister and then took him to task for failing to consult the committee over an earlier job with Indepen Consulting, a management consulting firm.

The last letter was dated on March 15. Yet in April, Mr Blunkett repeated the mistake by taking a directorship with DNA Bioscience, a DNA-testing company, without consultation. He also bought a three-per cent stake in the company for £15,000.

It has now emerged that he also worked for ORT, a charity. A spokesman for the charity, which also known as World ORT, said: “David Blunkett assisted World ORT, an educational and vocational training charity, with our international work and future development in the early part of this year.”

Mr Blunkett announced last night that he was organising the sale of shares he bought in DNA Bioscience. The shares had been put in trust for Mr Blunkett's three eldest sons after he returned to Cabinet on May 6.

Sir Alistair Graham, the parliamentary standards watchdog, said today that Mr Blunkett had committed a "clear breach" of ministerial code by ignoring the written advice from the committee, chaired by Lord Mayhew of Twysden.

In a letter to Lord Mayhew on March 3, Mr Blunkett apologised for the "misunderstanding" and also asked the committee to clarify whether an educational charity would fall within its remit. In Lord Mayhew's March 15 letter, he replied that work for a charity was covered if it was paid.

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