Bruce Anderson: Gordon Brown's efforts to enlarge Blair's 'big tent' are beginning to backfire spectacularly

The Prime Minister wanted Malloch Brown to be a decoration on the Christmas tree

Derek Wanless is a former banker. Initially chosen by Gordon Brown to review the NHS, he became the Blair government's health expert of choice. That upset Mr Brown. He does not like his dogs wearing other men's collars.

In early 2002, Mr Wanless was invited to No 10 to brief the PM. Gordon Brown was also there with his closest adviser, Ed Balls. The outcome was described by Tom Bower, in his biography of Mr Brown. "Just 10 minutes after Wanless began, the Chancellor and Balls began speaking loudly to each other. Wanless halted, stunned by the interruption. Blair was embarrassed, but said nothing ... Wanless resumed, addressing the Prime Minister ... Brown continued his animated discussion with Balls."

That is no way to run a primary school classroom, let alone a meeting in a PM's study. But "officials from the Treasury [were] accustomed to such behaviour". So were Mr Brown's cabinet colleagues, which explains why many of them had doubts about a Brown Premiership. Yet once Gordon Brown moved next door in Downing Street, there appeared to be a change. Ministers no longer had to decide whom they would like to please, the PM or the Chancellor (it being virtually impossible to do both). With Mr Brown in sole charge, life became easier.

There were other surprises. Most commentators had expected Gordon Brown to behave like a tribalist who usually butchered intruders. He had never been enthusiastic about Tony Blair's big tent. But he suddenly decided to enlarge it. To serve ministers, he recruited an Admiral, a director general of the CBI and a former deputy secretary general of the UN, Mark Malloch Brown.

Mark Malloch Brown was an especially interesting appointment. I have known him for nearly 30 years and have always delighted in his company while never agreeing with him. Mark abominates the neocons. He is a Europhile. He believes in international institutions, international law, multilateralism and the United Nations. He would like to restructure the UN Security Council to take account of current geopolitical realities. That would inevitably mean Britain and France losing their permanent memberships, with the consolation of a seat for the EU.

Lord Malloch Brown holds strong views and has never been backward in articulating them. Gordon Brown had no excuse for not knowing all about the man he was hiring, which made it an interesting decision. I assume that it signalled a significant shift in foreign policy. The new minister declared that Britain and the US would no longer be joined at the hip. His own appointment seemed to provide evidence that this would be true. Yet Gordon Brown quickly insisted that he and not Lord Malloch Brown would decide on policy towards the US. So what was going on? There is a simple answer: a dialogue of the deaf between over-confidence and solipsism.

Mark Malloch Brown could never be accused of lacking self-confidence. He believed that as a result of the Bush-Blair alliance, British foreign policy was in a mess. So when the new PM invited him to become a foreign office minister, Mark assumed that his job would be to put matters right. But that had never been Gordon Brown's intention. As Derek Wanless and many others have discovered, Mr Brown has no interest in ideas which contradict his own. He did not want Lord Malloch Brown to rethink British foreign policy. He wanted him to be a stylish decoration on the Christmas tree.

There was a further difficulty. While baffling the Prime Minister by acting as if he was entitled to have opinions, Mark also rubbed up against the new foreign secretary, David Miliband. It is extraordinary to recall that a mere few months ago, Mr Miliband was being widely written up as a future Prime Minister; I did some of the writing. He now forms part of a risible group of three along with the Chancellor, Alistair Darling, and the Home Secretary, Jacqui Smith. Never before have those three great offices of state been in the hands of such negligible figures.

To be fair to Mr Miliband, he has already broken one record in his brief period at the FO, as well as achieving something which everyone thought impossible. The record is his share price. No major politician's has ever fallen so fast, so quickly. Mr Miliband is the Northern Rock of front-bench reputations. The achievement relates to Margaret Beckett. David Miliband is making her seem competent. Admittedly, he is much more popular with officials than she was. But that is because he is likeable in a diffident sort of way, not because he is any good. Officials always prefer an amiable nonentity to a misery-gutted one.

Apart from being hopelessly out of his depth, Mr Miliband had another problem. The PM would obviously determine policy on the EU and the US. But in the negotiations which preceded his appointment, Mark Malloch Brown had asked to be allowed to attend Cabinet as well as taking charge of Africa and Asia. This did not leave much for Mr Miliband to do, except adopt children. As a result, he began to exhibit hitherto unsuspected depths – of insecurity. Mark Malloch Brown did not help matters. In an early interview, he described himself as the Foreign Secretary's "wise eminence". Well, someone ought to be, but when the need was so glaring, Mark was insensitive to draw attention to it.

Since then, there has been a campaign against him, led by Matthew d'Ancona, the editor of The Spectator. Mr d'Ancona's wife is Sarah Schaefer, David Miliband's special adviser. The couple vehemently deny collusion. But it is well known that with or without his adviser's help, Mr Miliband is out to fix Lord Malloch Brown.

Last week, an article assailing Mark Malloch Brown appeared in The Spectator. Apart from his views, the main ground of complaint was his accommodation. When he was appointed, Mark Malloch Brown took a considerable cut in salary. He is one of the very ministers who could earn substantially more out of government than in it. He assumed that if any organisation asked someone with a large family to move quickly to London – where he had not lived for 21 years and did not own a house – a home would be provided. But this is now being used as leverage by those who are trying to displace him. In self-pitying tones, The Spectator pointed out that David Miliband has not yet moved into the Foreign Secretary's official residence. More to the point, David Miliband has not yet moved into the Foreign Secretary-ship.

It seems likely that Lord Malloch Brown will not last long as a minister. The restraints on expressing his opinions are bound to irritate a man who cannot be accused of excessive patience. But apart from its amusement value, the whole affair is instructive. It tells us what we should always have known: that despite some fleeting illusions to the contrary, Mr Brown cannot run a government of strong personalities, only a government of ciphers.