Tony Blair's style of government was under the most sustained attack last night since he came to power more than seven years ago.
A former Cabinet Secretary accused him of taking advantage of a weak Parliament to push through bad laws, while David Blunkett disclosed the Cabinet rivalries "destabilising" relations at the top of the Government.
Lord Butler of Brockwell, who was the Cabinet Secretary to three prime ministers, said that Mr. Blair concentrated too much on securing the "best headlines" and was sidelining Cabinet government by taking decisions among small groups of people.
His attack, in an interview in The Spectator, was more direct and personal about Mr. Blair's conduct as Prime Minister than in his report on the intelligence failings before the Iraq war.
Michael Howard, the Tory leader, said it was "quite unprecedented and devastating testimony from someone at the heart of government". It confirmed that the Blair government was "obsessed with spin and headlines".
Lord Butler's intervention was a further setback for Mr. Blair after weeks of controversy over ministerial conduct and standards as a result of the publicity surrounding Mr. Blunkett's behaviour during a three-year affair with a married woman, Kimberly Quinn. He claims to be the father of her son and unborn baby.
A new biography of Mr. Blunkett, based on extensive interviews with him, confirms that there was a "genuine crisis" over Mr. Blair's leadership this year when Gordon Brown, the Chancellor, was manoeuvring to take over.
Mr. Blunkett told his biographer, Stephen Pollard, that Jack Straw, the Foreign Secretary, and John Prescott, the Deputy Prime Minister, had broken cover and "actively engaged in trying to destabilise Blair".
Mr. Blair staged a public show of support for Mr. Blunkett yesterday when they appeared in Sheffield to launch a drive against binge drinking. The Prime Minister told the BBC he had forgiven Mr. Blunkett for his disclosures and said he was confident that the Home Secretary would still be in place at the next election.
He described Mr. Blunkett as "a good friend" and said he should be judged on his record in office, such as pushing through measures to tackle anti-social behaviour.
Mr. Blunkett's candour has angered Westminster colleagues and is likely to undermine their support for him if the Budd inquiry into allegations that he fast-tracked a visa for Mrs. Quinn's nanny produces a critical report.
Mr. Blair has had to abandon previous declarations about the good personal conduct of ministers to accommodate Mr. Blunkett's private life. Now he has effectively allowed him to cast aside the traditional political conventions of Cabinet unity and discipline, which could encourage further disclosures by disaffected ministers.
Cabinet members have normally saved candid observations of their colleagues for their memoirs. No serving Cabinet minister has been as blunt or rude about fellow ministers as Mr. Blunkett.
Lord Butler retired as the Cabinet Secretary and head of the Civil Service a year after Mr. Blair became Prime Minister, having previously served John Major and Margaret Thatcher.
He had a further unrivalled insight into the intimate workings of the Blair government when he headed the inquiry into the pre-war intelligence failings on Iraq's weapons of mass destruction.
That report was scathing about the "informal way" decisions were taken around the sofa in Mr. Blair's den at No 10 without wider Cabinet discussion and consideration.
Yesterday Lord Butler broadened his attack to Mr. Blair's "bad government", saying that advisers were given too much influence in policy development and that Mr. Blair was making errors by excluding advice from civil servants.
He said there was "too much emphasis on selling, too much central control" and too little deliberation that included all the arguments.
Parliament did not have enough control over the Executive, which was free to bring in a "huge number of extremely bad Bills, a huge amount of regulation and to do whatever it likes" and too many decisions were delegated to unaccountable quangos.
No 10 defended Mr. Blair, saying that the Government should be judged "by the results it has achieved".
Mr. Blair's official spokesman said it was "not realistic" to suggest that every policy decision should be taken in Cabinet. Every week there were discussions in Cabinet on how government moved things forward and full use was made of an "active" Cabinet committee structure.
The spokesman said that Mr. Blair had "taken on board" Lord Butler's earlier criticisms of the lack of formal note-taking. But he refused to give details of specific changes of procedure that had been introduced to provide more informed collective judgment.
