The past seven days have been a watershed week in British politics. Gordon Brown may not yet have become prime minister, but already his prospective government appears to be foundering.

Writing this sentence causes me considerable embarrassment and regret. Embarrassment because I have mostly backed the Chancellor’s side in the endless Blair-Brown feuds and have consistently dismissed any prospect of a serious challenge to the Brown succession. Regret, because I have always believed that Mr Brown could potentially make an excellent prime minister and that he would certainly avoid the most egregious policy errors — higher taxes, increased regulation, kow-towing to trade unions — predicted by his detractors.

Why, then, do I now feel impelled to reconsider these views? The catalyst for the reassessment was last week’s Pre-Budget Report. But a single speech — even one that was foolishly overhyped in advance as a visionary manifesto for the “Brown decade” — could hardly justify such a reassessment. The real trouble is that the PBR was only the latest in a long series of unfortunate events, whose cumulative effect has been to emphasise the potential flaws that have always worried Mr Brown’s friends.

Perhaps the most worrying revelation about Mr Brown’s approach to politics has been his obsession with institutions and processes, rather than results. Everyone knows that Mr Brown’s proudest achievement has been the restructuring of the Bank of England, but is it possible that restructuring other government departments is Mr Brown’s “big idea” for the next decade? Following the merger of the Inland Revenue with the Customs and Excise, Brown allies hint at reorganising the Department of Trade and Industry, revamping the Cabinet Office and maybe even abolishing the Treasury itself. Even more depressing is Mr Brown’s apparent addiction to commissions and quangos run by former businessmen, financiers, civil servants and newspaper editors. It is as if the mere appointment of these commissions is enough to satisfy Mr Brown’s insatiable desire for information and the appearance of governmental activity.

On the substance of policy, meanwhile, Mr Brown seems to have nothing of interest to say — or do. Education, for example, is supposedly Mr Brown’s top priority for the “next Labour decade”. Yet his only positive idea in this sphere is to keep spending more money on school buildings and renovations, without any apparent regard to what these schools teach or how, until he achieves his newly proclaimed target — that the average cost of educating state school pupils should reach the amount now spent in private schools.

An even greater shock for Mr Brown’s supporters has come in his attitude to the environment. Having encouraged environmental campaigners to believe that he was on their side by commissioning a report on climate change by Sir Nicholas Stern, Mr Brown kicked them in the teeth by failing to show any active support at all for Stern’s main recommendations, whether on carbon trading, on carefully targeted environmental taxes or on substantial subsidies for energy efficiency and research. Not surprisingly, Sir Nicholas announced his retirement from the Treasury the very day after Mr Brown spoke.

But the worst disappointment of all for those who hoped that Mr Brown might represent a genuine new beginning for the Labour Government has been his attitude to foreign policy and Britain’s subservient relationship to President Bush. Until Mr Brown secured Mr Blair’s firm promise of departure, his uncritical backing for the Prime Minister’s foreign policy was tactically understandable, if not entirely admirable.

In the past few months, however, there have been growing signs that Mr Brown actually shares Mr Blair’s foreign policy views — or at least intends to follow the same approach, whether he believes in it or not.

Not only has Mr Brown refrained from hinting at even the slightest disagreements with the Bush Administration, even when he has had a golden opportunity to do so, for example, by endorsing the strong bipartisan backing in Washington for the Baker report on Iraq and criticising President Bush for refusing to negotiate with Syria and Iran. Even more disconcertingly, there are persistent and well-sourced reports from Washington that Mr Brown is eagerly trying to secure an invitation to the White House to create his own “special relationship” with President Bush. Some of Mr Brown’s supporters may believe that support for the Blair-Bush relationship may still be just a tactical feint, demanded by the principle of collective responsibility while Mr Blair remains in power. But this seems more and more like wishful thinking. At this rate, Mr Brown will be drawn so deeply into the Iraq quagmire and the special relationship with the White House, that he will find it impossible to extricate himself without facing charges of blatant hypocrisy and deception, when he actually comes to power.

If Mr Brown is really trying to ally himself with one of the most unpopular and incompetent presidents in American history — and one who will, in any case, be the lamest of ducks by the time Mr Brown comes to power — what are the implications for British politics and the Labour Party succession next spring? There seem to be only two possible answers. Either Mr Brown has lost his political judgment, or he is now so scared of doing anything bold or controversial that whatever judgment he had is effectively paralysed.

In either case, the prospects for a Labour Government that remained aligned with the Bush White House would appear pretty dire. Labour has until recently taken comfort in the fact that a swing of 8 per cent would be required for the Conservatives to win an overall majority in the next general election. What seems to have been forgotten, however, is that it would take only a 2 per cent swing to deprive Labour of its parliamentary majority and leave the balance of power in the hands of the Liberal Democrats and small nationalist parties. If Brown suffered such a 2 per cent swing and thereby lost the large Labour majority bequeathed to him by Tony Blair, he might not survive as prime minister after the election, since he would have led his party to defeat.

Until recently, Mr Brown and his allies had hoped to avoid such a fate by conveying the impression that the leadership transition in the Labour Party represented a sufficient change in government on its own. A new prime minister in Downing Street and a new Cabinet of ambitious, young Brownites were supposed to overcome the inevitable effects of boredom and disappointment. But Mr Brown, on his present form, risks becoming boredom and disappointment personified.

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