THE CHANCELLOR is gradually, one by one, removing the reasons for Tony Blair staying on as Prime Minister. Mr Blair says he wants decisions on the future of civil nuclear power to be taken before he leaves No 10. But even before the energy review is completed, Gordon Brown reveals his support for the nuclear option. Similarly, agreement has been reached on the tricky issue of pensions reform, and now we learn that the Chancellor is backing retention of the nuclear deterrent.

These disclosures are more about politics than policy. In each case, Mr Brown’s embrace of Blairism is ambiguous. Yes, he is fully committed to reform of public services, while being vague about whether he will continue with the whole Blairite choice agenda. Similar questions exist on nuclear power and pensions.

His comments on nuclear defence — “retaining our independent nuclear deterrent” and “necessary long-term decisions” — give no clues to the nature and timing of the replacement of Trident. There are big interlocked questions about how long the four submarines, the missiles and the warheads can be retained before they are replaced.

But that is not the point. On paper, Mr Brown has not gone farther than the Labour manifesto, but in practice he has hardened the commitment. Symbolism matters more than substance. What Mr Brown has been signalling recently is that there will not be a big shift in policy when Mr Blair goes. The risk, of course, is that public debate will be closed off, even though it is always possible to arrange votes in Parliament.

The corollary, of course, is that Mr Brown is increasingly alienating the hard Left. In denouncing his remarks on Trident, Clare Short said that she would no longer support him as the next party leader. Yesterday’s attacks from left-wing MPs and some union leaders provide Mr Brown with the enemies he needs to rebut false claims that he is a closet socialist who wants to take Labour to the left. He will not lose sleep over Unison’s vote yesterday against replacing Trident. It is in Mr Brown’s interests to face, and defeat, a left-wing challenger.

Yet we are no wiser about what a Brown premiership would be like. Talk of renewal by the Brown camp has gone little further than a reiterated plege on child poverty here and in Africa, and hints of a revived interest in constitutional reform. Mr Brown’s embrace of Blairism still leaves him a lot of freedom in practice. His main constraint is the much slower growth in public spending for the rest of the decade that he is due to announce next spring as a result of the comprehensive review.

But the biggest question raised by Mr Brown’s activity is what has Mr Blair still got to do? If his successor is going to accept his view on pensions, civil nuclear power and Trident, then the “legacy risk” appears much less. Mr Blair does not agree. He believes he still has a lot to do, as we will hear this afternoon in the first of “our nation’s future” speeches, on criminal justice. The danger for Mr Blair is that these will be seen as valedictory reviews, not agenda- setting, as the policy debate increasingly turns to Mr Brown and David Cameron.

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