Michael Howard has accused the government of misspending money on failed drives to cut truancy and process asylum seekers.

Calling on the prime minister to say whether Labour was planning post-election increases in national insurance contributions, the Tory leader said voters should expect the worst.

Insisting that taxpayers money had been wasted since 1997, Howard cited a National Audit Office report which slammed a £500 million expenditure on asylum applications.

He also claimed that the government had wasted £860 million in tackling bad behaviour and truancy in the country's secondary schools.

During the Commons exchanges, Howard said the country should be aware of the "billions of pounds of taxpayers' money" wasted by the prime minister.

Tony Blair, however, insisted that Labour was investing in public services in contrast to the Tories' time in office.

But he refused to give a clear commitment on Labour's medium term tax intentions.

"We will make our commitments on tax plain at the time of the manifesto as we have done before," he said.

"But when we're talking about waste, let me tell him of the waste that we have never been responsible for as a government. The waste on the poll tax. The Black Wednesday waste.

"And the waste of the three million unemployed when he was home secretary."

But Howard dismissed Blair's attempt to focus on the Conservative years. "It is no use the prime minister trying to throw back to the past," he said.

Immigration clash

The prime minister also said that under new government plans net migration into Britain "probably will fall".

And he said that Conservative moves to halve the immigration service budget "will simply make the problem worse".

There was also further criticism of "fantasy island" Tory plans for the offshore processing of asylum claims.

Responding, Howard cited a letter sent by the prime minister to the Greek government when that country held the European Union's presidency.

In the letter, Blair called for a discussion among EU leaders about a "transit processing centre" for asylum seekers.

"So he is interested in overseas processing centres too," said Howard.

"The difference between us is that he'd only do it with the EU and we'd do it on our own, and that he is all talk and we'll take action."

Howard added that "only a Conservative government can be relied on to bring immigration under control".

The prime minister said that most asylum claims were made within the UK, not at ports or airports.

"They could never be covered by any processing centre, and in any event the European Union - all the other countries - couldn't agree on a way forward [and] neither could the United Nations.

"So I come back and say to him, what is the country that is prepared to take Britain's asylum claims and process them?  There is no such country."