Brown's economics take on political flavour as he prepares for the succession

Gordon Brown is a political Chancellor. They all are, of course. Even Nigel Lawson, who luxuriated - until it all went horribly wrong - in the title of "the economists' Chancellor" was a street-fighter when it came to politics. But with Brown, the politics are blatant and more obviously all-pervasive.

Gordon Brown is a political Chancellor. They all are, of course. Even Nigel Lawson, who luxuriated - until it all went horribly wrong - in the title of "the economists' Chancellor" was a street-fighter when it came to politics. But with Brown, the politics are blatant and more obviously all-pervasive.

Yesterday's Budget speech was a transparent piece of electioneering. He had great fun with the Conservative plans, recently set out in a long, thoughtful and surprisingly unpolitical speech by his opposite number, Oliver Letwin.

"It has been put to me," Mr Brown said, that defence spending should be frozen. He did not agree. "I have also had representations," he said, that spending on the police, transport, housing, local government and services to the elderly and children should be frozen. He did not agree.

Playing fast and loose with the convention that Budget speeches should set out the policy of the Government rather than attack those of the Opposition, the House of Commons was lively, ignoring the convention that the speech is heard in silence. "I have received proposals," he went on, to cut the science budget and abolish the New Deal. He did not agree.

His own side loved it. His own side in the Labour Party, above all. Because Mr Brown is not simply a political Chancellor when it comes to taking the fight to the Conservatives, he is a political Chancellor fighting an internal battle in the Labour Party in which his every thought, word and deed is focused on the succession.

This was an electioneering Budget, designed to carry the Government through the next election and into the next Parliament, and also to carry Mr Brown through the Labour leadership election, whenever it comes.

This is not, as the Prime Minister and leader of the opposing faction in the party has said, an ignoble aim. But the way Mr Brown promotes himself can sometimes fall short of statesmanlike.

Which is a pity. Because if he did not manoeuvre and politick so blatantly he would still be the undisputed heir to the New Labour inheritance, indeed, more so, because he would not have made so many enemies in the party.

The politics tend to obscure the fact that Mr Brown's record as Chancellor is genuinely outstanding, bearing comparison with that of David Lloyd George, whose record for sound economic management combined with social reform was unrivalled for 82 years. Tony Blair may have been premature to compare him to Lloyd George after his first Budget in 1997, but he has been vindicated.

Mr Brown was within his rights yesterday to boast that "Britain is enjoying its longest period of sustained economic growth for more than 200 years". Much of that record is owed to factors beyond Mr Brown's control, but some of it is not, and it is quite exceptional - since Lloyd George's day at least - for a British Chancellor not to contribute to economic crisis.

The grade-A insight into understanding Mr Brown's success is provided by William Keegan's new book, The Prudence of Mr Gordon Brown . This magisterial overview believes that Mr Brown is an economic success precisely because he is such a political Chancellor.

From the book, we can see how contingent and opportunistic many of the positions adopted by Mr Brown have been. Independence for the Bank of England was the culmination of an accident-prone search for a reliable mechanism for controlling inflation since the 1970s.

After attempts to control the money supply failed, Mr Lawson tried to peg the pound loosely to the Deutschmark; after he went, John Major bounced Margaret Thatcher into the exchange rate mechanism, a device for linking the pound more closely to the Deutschmark. Nearly everyone in the universe thought this was a brilliant idea. Mr Keegan did not, so he is entitled to point out that, when the policy went belly-up, Mr Brown, who had just become shadow Chancellor, was in just as much trouble, intellectually, as the Major government which was destroyed.

But Mr Brown's speed and sharpness in learning the lessons of that policy failure and finding an alternative route to "stability" - an independent central bank and prudent rules for borrowing - laid the foundations of his stature today. There is a lot to be said for ruthless pragmatism, especially in economic policy.

Yet sound economic management is only half of Mr Brown's achievement. The other half is his success in promoting social justice. This is under-appreciated for two reasons: one, it started late, because for his first two years Mr Brown froze public spending; and, two, because the Blair-Brown strategy is to pursue egalitarianism by stealth. In both cases, reassuring floating voters is considered more important than Labour crowd-pleasing.

There is a tension here between Mr Blair's desire to reassure middle-income England and Mr Brown's desire to please the Labour crowd, but it is a tension within the Chancellor as much as between him and his next-door neighbour. He recognises he is running for Prime Minister, not Leader of the Opposition. Yet his record of redistribution since 1999 is remarkable. Making incomes more equal is hugely difficult, although making incomes more unequal by creating mass unemployment is relatively easy, as the Thatcher Government found.

Mr Brown's record, of lifting a million children and 1.2 million pensioners above the official poverty line in just five years is astonishing. Nor is this mere Government propaganda. In fact, the Government is so stung by past accusations of spinning that Mr Blair and Mr Brown consistently underclaim their achievement, saying only 600,000 children have been lifted out of poverty; the higher figures are produced by the independent Joseph Rowntree Foundation.

Robin Cook is typically acerbic. "Labour keeps such progressive policies under the counter in a back room where members who know where to find them can slip in and admire them while the spin doctors are not looking." But at least they are there. Where Mr Brown seems to be pushing his internal party ambition against the wider interest of the party is over the next phase of public service reform.

Over the past 18 months, he and Mr Blair have clashed openly on the issue of opening up the NHS and other public services to independent providers. Mr Brown said in a speech to the Social Market Foundation that equality in the health service could only be guaranteed by "public provision", a curiously Old-Labour statement contradicting the party's manifesto, which promised new surgical units "managed by the NHS or the private sector" to cut waiting times.

Today is the fifth anniversary of Mr Blair's promise to abolish child poverty within 20 years. Unmarked and unheralded, and thanks to Gordon Brown's skill, he is a quarter of the way towards that target, right on time.

Mr Brown's stature as Chancellor is beginning to look truly impressive.