Michael Howard has clashed with the prime minister for the first time since becoming Tory leader.

Challenging the prime minister on the £7 billion in extra Whitehall administration costs, the Tory leader said the government's record was one of "ineffectiveness, ineptitude and incompetence".

To cheers from his own backbenchers he took Blair head on - and dismissed a scathing attack on his own record in government.

Before answering his opposite number's questions, the prime minister welcomed Howard to his new position.

"First of all I should welcome the right honourable gentleman to his new position and to say how delighted I am that someone written off under the last Conservative government has been given a chance to rehabilitate himself under Labour," he said.

But the pleasantries ended there. The prime minister said Howard "doesn't simply represent the past... he would take us back to the past".

Howard had been a part of a government which presided over 15 per cent interest rates, a million extra unemployed and one million people trapped by negative equity.

"Let me say one other thing. Whatever this side has done, none of us when in government introduced anything as bad as the poll tax," said Blair.

Howard, said the prime minister, was simply a reminder of the "same old people, same old policies, same old Tories".

But the new Conservative leader was forearmed for the attack on his record in the Thatcher and Major governments.

"Let me make it absolutely clear. I am very happy to debate the past with the prime minister, any day he likes. I have got a great big dossier on his past. And I haven't even had to sex it up," he said to cheers from his backbenches.

"We can talk about his personal pledge to leave the European Union. We can talk about the time that he criticised America's 'state sponsored terrorism', I wonder if he will be raising that with President Bush next week?

"Or we can talk about the time he praised the 'fortitude and resolve' of the Wapping strikers. I bet he doesn't remind Rupert Murdoch of that.

"I am very happy to debate the past with him any day of the week. But I'd rather think that the British people are more interested in today and tomorrow than yesterday. And I will take every opportunity to remind them of the failures today of his discredited government."

For Blair, however, the issue was not just Howard's history. "I am very happy to debate today with him as well. Let's look, for example, at his own constituency and what has happened today," the prime minister told MPs.

"In his constituency 11 schools have benefited from the New Deal for Schools funding which he's pledged to scrap.

"The number of five, six and seven year olds in classes of over 30 has fallen from 12,000 to 249."

"We have had the best results for primary schools, GCSEs, A Levels that we've ever had.

"All the waiting times are down...and that is precisely the difference. That this party is putting money into public services, getting results in every constituency in the country.

"And what we know for him is that he doesn't simply represent the past, he would take us back to the past."