Claims that the centre of government is too 'fragmented' are among the findings of a report based on interviews with senior officials.

The new study, published by think-tank the Institute for Government (IfG) and entitled 'Shaping Up: A Whitehall for the Future', claims there is a 'conspicuous lack of a single coherent strategy for government as a whole', and calls for improved coordination between Downing Street, the Treasury and the Cabinet Office.

The report also says the prime minister's office has too much power in relative terms. 'The office of the British prime minister holds a concentration of formal power greater than that of almost any other country in the developed world,' the authors conclude.

'In contrast, the fragmentation and lack of coordination at the centre of the civil service - the Treasury, Number 10 and the Cabinet Office - leads to an administrative centre that is relatively weak. This curious situation has created a strategic gap at the heart of British government, which inhibits the ability to set overall government priorities and translate them into action.'

But the report makes clear that many of the senior civil servants, interviewed anonymously, are 'ambivalent' about the prospect of a more powerful centre of government.

'While they wanted stronger leadership, they were also concerned about the potential for micro-management and poorly co-ordinated central initiatives,' the report stated.

It quoted one official as saying: “I think making the centre bigger would be a disastrous thing to do, because what that would do is mean that you’ve got a bigger problem to manage.”

Sunday newspapers reported damaging comments about Number 10 made by one departmental director-general, though left out of the IfG report. “What comes out of Number 10 is lots of barmy ideas,” the unnamed official allegedly said. “It's the worst possible kind of policymaking, which is 'here is a problem, let's have a kneejerk reaction to it tomorrow on what we’re going to announce', and quite frankly the less contact with Number 10 the better.”

Speaking to the BBC this morning, one of the report's authors, IfG research director David Halpern, said the UK now conferred a lot of power on its prime minister, “but we haven't really modernised the way Whitehall operates around him or her”.

Halpern called for the Cabinet Office to take a stronger role in setting strategic direction for the whole of government – losing extraneous policy functions such as social exclusion - and ministers to lay a more active role in the governance of their departments, particularly through executive boards.

A Cabinet Office spokesperson said the department would study the report, but rejected the suggestion that the centre of government was badly coordinated, citing the reaction to the financial crisis.

“We do not accept the conclusion on Cabinet Office, Number 10, and HM Treasury coordination,” they said.

"For example, over the last 12 to 18 months we have worked very closely together and with other departments to develop and drive the government's policy response to the global recession, through the establishment of the NEC (National Economic Council) and its supporting secretariat - indeed, there has been unprecedentedly close coordination between the Treasury and Cabinet Office in this area."