Tony Blair's informal style of decision-making and reliance on a small coterie of advisers has come in for stinging criticism in the Butler Report. So is it the end for Mr Blair's "sofa cabinet"?
By Brian Wheeler
BBC News Online political reporter
With his chinos, open-necked shirt and breezy "Hi Guys!" manner, Mr Blair has always tried to reject the stiff formality of Whitehall.
Is Mr Blair taking his cues from the West Wing?
He reportedly began his first cabinet meeting in 1997 by telling ministers "Call me Tony".
Decisions are often taken over a cup of tea on the sofa in Mr Blair's No 10 office - known to insiders as "the den" - rather than in formal, minuted committee meetings.
If he is taking his cues from anywhere, you suspect, it is slick US drama The West Wing, in which President Martin Sheen sweeps through the corridors of power making decisions on the hoof, rather than, say, the traditional British model parodied so effectively in Yes, Minister.
But - following Lord Butler's criticisms - Mr Blair's comfy office sofa could find itself consigned to the nearest skip - or, at the very least, traded in for a larger model, with room for a civil servant to perch on the end, notebook in hand.
"This shirt-sleeve, sitting on the sofa, 'call me Tony', chummy form of government would have appalled Lord Butler," says George Jones, emeritus professor of government at the London School of Economics.
....Or Yes, Minister?
Prof Jones said Tony Blair had brought into government the style of leadership he had used very effectively in opposition.
"He almost seemed to despise collective decision making. He had been used to working with a small group of like-minded cronies," Prof Jones said.
As Cabinet secretary, Lord Butler had lost a battle with Mr Blair over political advisers being given the power to issue orders to civil servants, he added.
And, in some respects, the Butler report represented the "revenge of the civil service of traditional (non-politicized) values".
Traditionally, British governments formulate policy collectively in Cabinet - and take collective responsibility if it goes wrong.
But according to Lord Butler - whose findings were accepted in full by Mr Blair - this system, with its safeguards and balances, was undermined by the government's disregard for Whitehall convention.
"The informality and circumscribed character of the government's procedures which we saw in the context of policy making toward Iraq risks reducing the scope for informed political judgment," the report said.
Furthermore, Lord Butler adds, papers written by officials were not circulated or discussed by ministers.
This meant members of the Cabinet were asked to lend their name to decisions to which they had made little input.
"Without papers circulated in advance, it remains possible to but is obviously much more difficult for the cabinet outside the small circle directly involved to bring their political judgement and experience to bear for which the cabinet as a whole must carry responsibility," Lord Butler concludes.
The lack of minuted meetings also means the decision-making process cannot be held up to proper scrutiny after the event.
Of course, Mr Blair is not the first prime minister to be accused of surrounding himself with a clique of like-minded advisers.
Harold Wilson had his "kitchen cabinet" and Margaret Thatcher was regularly criticized for riding roughshod over her cabinet or listening too closely to those she considered "one of us".
In the run up to the Iraq war the key members of Mr Blair's inner circle would have included:
Jonathan Powell - Downing Street chief of staff and younger brother of Charles Powell, one of Margaret Thatcher's closest advisers
Alastair Campbell - Downing Street communications chief until stepping down last year
Lady Morgan - director of government relations, in charge of smoothing relations between Mr Blair and the Labour Party, a vital role in the run up to war
We know from evidence to last year's Hutton report that meetings at Number 10 could turn into rambling day-long affairs, with trusted Cabinet colleagues such as Jack Straw and Geoff Hoon dropping by to add their views.
At times, the Hutton evidence conjures visions of Whitehall mandarins jogging a few paces behind the key players with notebook in hand, trying in vain to keep a record of discussions.
According to new biography by Anthony Seldon, Mr Blair "shifted power inside No 10 and then into the Den".
"That is OK, but when it comes to something as vital as taking Britain into war, it was not enough," he writes.
Lord Butler, who served as Cabinet secretary under Mrs Thatcher, John Major and Mr Blair - until he resigned in 1998 - was not impressed by this new approach, he adds.
Number 10 has promised to change its procedures, in the light of Lord Butler's report.
A new Civil Service Bill, to be published in the autumn, will reportedly order more key meetings to be minuted by civil servants.
But it may prove difficult to change the habits of a lifetime.