Fifteen days to go. It may look messy but the seemingly endless handover in 10 Downing Street, feeling rather like a very long flight to the Far East, will not only end soon but may turn out to have been beneficial.

The downsides are obvious: lack of direction at the centre of Government; nervous anticipation by ministers and civil servants about what Gordon Brown wants; the self-indulgent Labour deputy leadership contest; and Tony Blair’s globetrotting.

But there are always upsides, certainly in the view of those at the heart of Whitehall who are preparing the handover. As one very senior civil servant said to me last week: “I have rather got to like long transitions. The outgoing Prime Minister is away from London a lot on his travels and his successor, now certain of the job, has the freedom to think and plan.”

The key is time. Normally changes in the structure and personnel of government are carried out when leading politicians are least fitted to do so – when they are exhausted on the Friday after a long and draining general or local election campaign. Of course, officials prepare options but the crucial ministerial changes cannot be made until then. No wonder mistakes are made, invariably so in Mr Blair’s annual reshuffles.

Blair casts himself as EU president candidate

Speaking on French TV, Tony Blair sang the praises of the EU and sketched his agenda for its future, all in fluent French

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By contrast, Mr Brown does not have to rush on June 27 or 28. He can prepare now. His freedom of manoeuvre has been increased by the growing list of ministers stepping down: Hilary Armstrong joined Mr Blair, John Prescott and John Reid yesterday. At least two or three other ministers could go or be dropped. Either way, we are going to see the largest Cabinet reshuffle since Labour came to power in 1997. No one yet knows who is going to get what job. Mr Brown is being inscrutable even with close allies.

In parallel, he is discussing changes to the machinery of government. We are not going to see a prime minister’s department, as recently urged by Sir Michael Barber, the former head of the Delivery Unit. The Brown camp does not want to give the appearance of presidentialism: rather the reverse. (A critical analysis of this trend appears in a new paper by Andrew Blick and Professor George Jones on the history and policy website of the Centre for Contemporary British History.)

Any structural changes are likely to be evolutionary: adjustments to the remit of the Department of Trade and Industry (the fate of energy being crucial); a further division between the centre and the administration of the NHS; and over the future of the Scotland and Wales offices and the responsibility for constitutional reform.

Sir Gus O’Donnell, the Cabinet Secretary, is playing a key role, partly based on his own innovation of capability reviews analysing the strengths and weaknesses of departments, 12 so far, not including the Treasury. As Sir Suma Chakrabarti, Permanent Secretary at the top-rated Department for International Development, notes in an interview in Whitehall and Westminster World, however, there are tricky questions about the responsibilities of ministers and officials, particularly where “day-to-day politics are more difficult”. The challenge for Mr Brown in a fortnight will be to get both structure and people right. He has no excuses if he misuses his unique opportunity.

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