Gordon Brown today pledged not to abandon Tony Blair's ambitious 'legacy' agenda for schools, hospitals and welfare when he takes over the leadership of the Labour party.

The Chancellor made the promise as he gave media interviews to defend yesterday's pre-Budget Report, in which he announced a £2bn-a-year tax increase on North Sea oil profits in order to help fill a black hole in public spending.

Despite accusations that his iron grip on the exchequer was slipping, the Chancellor said that the economy remained well placed for the future.

In an interview with the BBC Radio 4 Today programme he spoke as if his succession to No 10 was assured, as he emphasised that he would not slacken the pace of Mr Blair's reform programme when he takes the reins of the Labour party before the end of this Parliament.

Asked if a Brown government will be the same as a Blair government, he did not bother to make the caveat that his succession was not a foregone conclusion. He said: "Exactly."

Mr Brown said that economic stability, low inflation and rising employment indicated that Britain's economy had successfully weathered the toughest period of his eight years at the Treasury.

"The question you have got to ask is are you now well positioned for the future? And I believe that the economy is. I think most people, when they see low inflation and high employment, know that is the case," he told the BBC.

Mr Brown’s optimism comes after he was forced to halve the growth forecast for the current year to 1.75 per cent, from the 3-3.5 per cent he predicted just eight months ago.

At the same time, borrowing will rise £5 billion above his Budget forecast to £37 billion. The admission was described a humiliation by Conservatives which left the Iron Chancellor's famed golden rule - which says that over an economic cycle he should borrow only to pay for investment spending - "tarnished and discredited".

Mr Brown was unfazed by the criticism from the oil industry over a £2bn windfall tax on profits, which have soared in line with rocketing prices in the past 12 months. Oil industry spokesemn have warned that the rise may restrict investment in the North Sea. Mr Brown said that the money would be redistributed to pensioners and motorists.

Malcolm Webb, chief executive of the UK’s Offshore Operators Association, said: "It is almost beyond comprehension that the government has failed to grasp the vulnerability of the industry’s future in the UK. It will deter investment in new fields and make older fields less attractive for increased recovery."

Nevertheless, the report, outlined in Parliament yesterday, was widely seen as preparing the way for a Brown premiership. The combined taxes and cuts on public spending should ease pressure on public finances and bring the Budget back into surplus by 2008, a year before the next election, which he expects to fight as Prime Minister.

Although refusing to be drawn on a timetable for the handover of power, he appears to hoping that the public will reward him for taking difficult decisions and steering the economy though a difficult spell without a recession.

The Labour leader-in-waiting took a pre-emptive swipe at David Cameron, his likely opposite number following the announcement of a result of the ballot of Conservative members at 3pm today.

"We've had Tory leader after Tory leader. I've had, I think, seven Shadow Chancellors. Every time a new person is appointed people say this is all going to be different - I've looked at Conservative policy and it's simply a rebranding of an old policy with a new gloss.

"The fact is that the Conservative’s rule on public spending would mean that there would be £12 billion cuts in public spending this year and that would mean we would not be able to finance our health, our education and our public services."

Asked whether he was concerned about looking "shop-soiled" in comparison with the fresh-faced 38-year-old he replied: "I think that's a bit unfair. I'm a father with a two-year-old child ... I feel pretty young, actually."

Mr Brown indicated that he would continue the Blairite agenda of modernisation in health and education, which includes such measures as university tuition fees and the extension of borrowing levels for foundation hospitals which he had previously been thought to have opposed.

"We work as a team and .. despite what you might read, we've always worked as a team. I don't think anybody should be in any doubt that not only will reform continue but in future years this will be intensified," he told Radio 4's Today programme from Brussels.

George Osborne, shadow chancellor and Mr Cameron’s campaign manager, said today that the forecast of £12 billion of public spending cuts under the Conservatives was "complete rubbish".

He said: "We are talking about a Conservative government in four or five years’ time. We have no idea what state the public finances are going to be in when we take over if the British people put us in government.

"We have got no idea what mess Gordon Brown will have made of the economy by then... to put specific figures as Gordon Brown is trying to do, I think, shows he is rattled."

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