Gordon Brown has been told that he must increase his powers if he wants to make reform of public services a reality.

The advice comes from the man who established Tony Blair’s Delivery Unit at No 10 in 2001 and ran it until 2005, in close collaboration with Mr Brown and the Treasury.

In his new book, Instruction to Deliver, which The Times begins serialising today, Sir Michael Barber calls on the next Prime Minister to use his honeymoon period to establish a new “department of the prime minister and the Cabinet” to drive through reforms.

Sir Michael’s words, though politely phrased, suggest that Mr Blair could have done much more as Prime Minister with better organised back-up from the Civil Service and advisers. Mr Brown, he says, should unapologetically justify it on the ground of effectiveness, enabling clarity to replace fudge in Whitehall.

But Sir Michael, the most senior of former Downing Street advisers to write about life under Mr Blair, also suggests that public service reform may have been hampered by the division of power between Mr Blair and Mr Brown.

It caused “dilemmas and sometimes downright confusion” in the departments Mr Blair had depended upon to deliver change, since ministers and officials had “to pick their way across a minefield”.

He says that because the job of Prime Minister has become so stretched and demanding, the Prime Minister’s powers should be strengthened, not weakened. Prime ministers “carry a far heavier burden than other Cabinet ministers” but are the only ones who do “not have a department or ministerial team to share the burden”.

The proposal for a prime minister’s department is unlikely to be grasped by Mr Brown, though he may be more sympathetic to other proposals for improving the Treasury and the Cabinet Office.

Although an admirer of Sir Michael, Mr Brown has made plain that he wants to move away from any suggestions of a presidential style of leadership inside No 10. An ally said that Mr Brown would be aiming to give more responsibility to Cabinet ministers to deliver reform.

At a debate organised by the Fabian Society in Central London last night, featuring leadership candidates Michael Meacher and John McDonnell, Mr Brown distanced himself from the rest of his party, stating that Labour could not “go back to the old arguments of 20 years ago”.

Mr Brown also claimed that the world was entering an era of “new multilateralism”. He cited Darfur as one of the most pressing problems and in a reference to a nofly zone that is currently under consideration at the UN, Mr Brown said: “It is right to intervene, we have got to make sure it is done in the right way”. Tony Blair’s reign as Labour leader will end on June 24, three days before he stands down as Prime Minister. The party said that his successor would be announced at a leadership conference to be held in Manchester.

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