Until five weeks ago, the allnight shift for Downing Street’s four duty clerks was relatively quiet.

On occasion they would be called upon to wake the Prime Minister to deliver an urgent message. But for the most part the early hours in Downing Street were viewed by whoever was on duty as a time for drinking coffee and reading, free from interruption.

That has all stopped now. In the past month the duty clerk has had to get used to the idea of the Prime Minister wandering through from No 11 – in the flat above which he and his family now reside – at all hours to ask what’s going on.

And while the rest of the Civil Service may just be stirring at 6.30am, the Prime Minister has been up for up to an hour and, having listened to Wake Up to Money on BBC Radio 5 Live, is ready to roll. His first stop will be the small office downstairs – Tony Blair’s den – where Mr Brown has his own computer and a big television screen, which he hopes to use one day to watch sporting events.

Alone with the duty clerk, Mr Brown will browse through the papers and look at his diary for the day. The clerks are not the only ones to have their early morning interrupted by Mr Brown’s hyperactivity.

It is just over a month since he assumed office, and the Government and Labour Party are quickly realising that there is nowhere to hide from Britain’s 52nd Prime Minister.

His weapon of choice is the mobile phone, which will ring from 6.30am, with the bright-eyed, perky Prime Minister demanding papers, discussing strategy and even asking for feedback.

“You can literally hear the spoon going into the cornflakes as he’s talking,” one member of the Government who has received the early call said. “He is a very early riser and he goes to bed quite early, which is not good for the body politic, which mostly consists of people who go to bed late and are not early risers.”

One policy adviser said that this approach was not always helpful. “Government by sofa has been replaced by government by mobile phone. When Brown wants something, he goes direct.

“It’s sometimes awkward because it means he by-passes the Whitehall machine and we don’t know what is happening.”

Another said: “We’ve got to the point where people deliberately avoid taking a call because he phones up so frequently. If you float an idea, he will ask you to write a policy paper on it and he’ll keep phoning you until you’ve written it. It’s absolutely nonstop.”

When Mr Brown took over, he was determined to show that he was a man of depth, rigour and hard work. But so far it is his style of governing, rather than the substance, that has provided the most marked contrast, as officials who worked under Mr Blair testify. The novelty of being Prime Minister seems unlikely to wear off soon, with Mr Brown enjoying pulling the levers of power.

On his trip to the US this week, the pace was relentless, with Mr Brown delivering a 16-page speech to the UN and taking questions for half an hour from representatives, all before 8.45am. He then swept out of Manhattan in a 20-car convoy and left the country before most New Yorkers had begun work.

The week before, with the floods at their height, Mr Brown woke at 5am, spoke to the new Turkish Prime Minister and boarded a helicopter for a flight over the flood chaos affecting the West of England. He returned to Downing Street where, at 11am, he went to his first press conference.

That afternoon, as the Gloucestershire power station looked under serious threat, he kept a small group of Cabinet ministers – Ruth Kelly, Ed Miliband, Hilary Benn – and senior officials in No 10 from 9pm so that they could answer requests for help from the area. It was 1am before he told them that they could go home.

By 7.45am, having already been up for 90 minutes, Mr Brown was chairing a meeting of the Cobra emergency committee. When Mr Blair bowed out of office he said he had “never pretended to be a great House of Commons man”, but Gordon Brown cannot get enough. He has already made three statements to the House – on constitutional reform, the draft Queen’s Speech and national security – something which Mr Blair never did.

In addition, there have been almost daily policy statements from Cabinet colleagues, which he frequently sits through, nodding in a headmasterly fashion at members of Team Brown.

Allies suggest that this fetish for Parliament is born of bitter experience. In 1997 he incurred the wrath of the Speaker, Betty Boothroyd, when he announced the independence of the Bank of England at a press conference rather than on the floor of his House.

There is a handful of sceptics. One MP said: “I couldn’t tell you about the contents of one of those statements and nor could the voters. But they all know about the floods. Given the scale of the problems, surely it would have been better to delay all these announcements to show your flexibility and show you were focusing on the floods.”

One source said that Mr Brown’s courtesy and keenness to engage, even those whom he sacked or demoted in the reshuffle, have helped to keep MPs on side. But even this noted Brown sceptic admitted that the public seemed to approve of Mr Brown. “We [in the Parliamentary Labour Party] have moved from one extreme to the other. It’s amazing to think that six weeks ago we were all worried about losing our seats.”

Mr Brown’s spinners are keen to get the message out that Cabinet, now on a Tuesday rather than a Thursday, is at the heart of the Brown Government. Mr Blair’s Cabinets would involve presentations from ministers and civil servants and cursory discussion. Mr Brown, by contrast, goes round the table, demanding contributions from everyone.

One example given to show the Cabinet’s influence is its changes to the constitutional reforms programme. According to Cabinet sources, they were very “lawyerly” when presented before Cabinet, concentrating on a Bill of Rights and a written constitution.

“But as it went round the table, people said it was worthy but not very exciting. It was down to Cabinet members that easier-to-understand measures were introduced, such as weekend voting.”

There have been flashes of “old Gordon”. There was a glimpse of Stalinist anger after comments by Douglas Alexander, the International Development Secretary, and Lord Malloch-Brown, the Foreign Office Minister, suggesting that Britain should distance itself from the US. Within hours, he had instructed his top official to write to the Cabinet to refrain from making remarks that could be interpreted as a weakening of his Government’s support for US foreign policy. Dissent, it seems, will not be tolerated.

The US trip also showed his weakness when under strain. By the end of the trip, with his facial features sagging visibily through tiredness, interviewers saw a return to “bulldozer Gordon”, giving aggressive, rambling, unfocused answers. The return of serious Cabinet government has prompted some rather heavy “what if?” soul-searching among the ministers who have made the transition from Blair to Brown.

Would Britain have gone to war in Iraq if Mr Blair had been operating the style that Mr Brown has brought to No 10 in his early days? The thought has crossed the mind of ministers who felt that they had no choice because the decisions were being made elsewhere.

One told The Times with obvious regret that Mr Blair had not initiated a serious Cabinet discussion about the war until thousands of troops were massed ready for action, and when it was far too late to say “no”.

A manic month

June 27 Becomes Prime Minister

June 28 Announces new Cabinet; splits Education Department

June 30 Glasgow airport attack

July 3 Constitutional reform announced

July 4 First Prime Minister’s Questions. Review of NHS services

July 5 Announces £400 million of extra funding for schools

July 7 Visits flooded residents in Hull and Toll Bar near Doncaster

July 9 Outlines Government’s priorities to the Cabinet. Holds meeting with José Sócrates, President of EU Council of Ministers and the Prime Minister of Portugal

July 10 Statement on schools; announces new academies and strengthens links with universities

July 11 Draft legislative programme outlined to Parliament; includes 3 million new homes. Signals he will abandon supercasino. Meets Ban Ki Moon, UN Secretary-General

July 13 Announces funding for five hours of sport a week in schools

July 16 Travels to Belfast to meet Bertie Ahern, the Irish Prime Minister, and the leaders of the devolved government, the Rev Ian Paisley and Martin McGuinness. Flies to Berlin for a meeting with Angela Merkel, German Chancellor

July 17 David Miliband, the Foreign Secretary, expels four Russian diplomats because of Moscow's failure to extradite chief suspect in murder of Alexander Litvinenko

July 18 Announces review of the declassification of cannabis

July 19 Ministers reveal past experiences with cannabis

July 20 Travels to France to meet President Sarkozy

July 22 Chairs Cobra meeting on the flooding

July 23 Visits flooded towns. Announces evaluation of the 24-hour drinking laws

July 24 Chairs Cobra meeting

July 25 Makes security statement; visits flooded areas; announces aid will be boosted to £46 million

July 29 Travels to Camp David for discussions with President Bush

July 30 Travels to New York; meeting with Bill Clinton

July 31 Speech at the UN

August 4 On holiday

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