Gordon Brown took to the airwaves to defend his Budget this morning as the Conservatives continued to insist that the Chancellor had "conned" the British public by claiming to cut income tax yesterday.

The Chancellor appeared to give himself a popularity boost before his likely accession as Prime Minister by reducing the headline rate of income tax by 2p yesterday afternoon.

But it became clear that the cut would largely be financed by abolishing the 10p starting rate of income tax — a decision that will hurt low-earners — and a series of green taxes.

Mr Brown repeated his assertion today that the reforms would leave the average British household £100 better off and rejected Tory criticisms that he was raising taxes on the poorest while granting relief to middle class families.

“That’s absolute nonsense,” he said, describing the changes as a "simplification" and the biggest tax reform for 20 years.

“I’ve tried my best by everyone. On average, it’s £100 per household better off, for families with children about £250 per household. And what I’ve tried to do is look at the needs of particular groups as we make this major change in the tax system," Mr Brown told BBC Breakfast.

"It’s a major reform in a fiscally neutral Budget, the right thing for the economy at this time. I felt it right that we dealt with some of the anomalies in the tax system and dealt with them now.”

“I’ve tried to look at what is happening to each of the groups — families with children, pensioners and the low-paid workers — and I’ve tried to do my best to ensure they are better off, he said.

Mr Brown countered Conservative claims that the abolition of the 10p starting rate would disproportionately hurt the poor, saying that increases in the personal tax-free allowance for pensioners and an extra £1 billion in working tax credits would soften the blow.

But that did not stop George Osborne, the Shadow Chancellor, following Mr Brown from studio to studio, accusing his counterpart of stealing Conservative ideas and deceiving the public with what he described as a "stealth Budget".

“No-one listening to the Budget yesterday would have worked out the whole thing is a con-trick," Mr Osborne told BBC Radio 4's Today programme. “Their income tax bill went up yesterday and I don’t think listening to that Budget they would have thought that."

Mr Osborne continued the attack on GMTV, claiming that the Budget would leave 3.5 million families worse off and that those with incomes between £5,000 and £18,000 would see their tax bill rise rather than fall.

“Watching Gordon Brown, there’s no way you would have known that. He pulled a con trick. People will have heard Gordon Brown announcing a big tax cut. When you get to the small print, you realise he’s taking all the money off you."

With the income tax cut scheduled to come into effect next April — when Mr Brown is expected to have been Prime Minister for nearly a year — the controversy over the Budget spilled into questions about the Chancellor's behaviour as a leader and the plans for his succession.

Mr Osborne said that yesterday's Budget demonstrated Mr Brown's "stealthy" characteristics. “Sadly, that is not the quality we want from someone who is going to be our Prime Minister," he told GMTV.

The Chancellor, for his part, would not be drawn on BBC Breakfast over whether the income tax reduction — considered by many a ploy to reassure middle-class voters — presaged a plan to call an early general election to give legitimacy to his takeover as Prime Minister.

“Nothing in politics can be taken for granted”, said Mr Brown.

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