Labour and the Conservatives have continued to challenge each other over plans for tax rises and spending cuts.

Following the unofficial launch of the general election campaign on Monday, senior Labour ministers sought to portray the Opposition as wedded to massive spending cuts.

But the Conservatives hit back, saying that if the government is re-elected it will be forced to put up taxes to pay for its spending plans.

A series of challenges and rebuttals throughout Tuesday indicated the importance both parties place on not being forced onto the defensive on the issue.

Tax and spending policies are set to form one of the major battlegrounds as Westminster prepares for an election now widely expected to take place on May 5.

Challenge

John Prescott called on the Tories to publish the full details of the James review, which identified the savings the party would make if elected to government.

"It is now clear the Tories cannot or will not publish the James review in full. They know it will not stand up to public scrutiny," said the deputy prime minister.

"If the Conservatives do not have enough confidence in the James review to publish the report in full why should the public have any confidence in it at all?"

Meanwhile, the Conservatives challenged Tony Blair to say which taxes he would raise if Labour win the next election.

"Yesterday we showed how we will spend £12 billion less than Labour by getting better value for money," said  shadow chancellor Oliver Letwin.

"We will use £4 billion to reduce taxes. We will use the remaining £8 billion to reduce borrowing and avoid Mr Blair's next round of tax rises.

"Independent experts have said Mr Blair is borrowing too much. We have a plan to reduce that borrowing.

"Mr Blair does not. It's time he told the truth on tax. So today we are asking him 'Which taxes would you raise?'"

The party warned that the government could put VAT on food or increase the basic rate income tax by two pence.

For Labour, Treasury minister Paul Boateng insisted the party had set out clear spending plan.

"The party whose figures do not add up is the Tory party," he added.

"No one will believe their claim that they can cut taxes, cut borrowing and increase spending all at the same time, because the savings they claim to have found through the James review just don't add up."