The prime minister has refused to rule-out further tax rises to fund the NHS.

Speaking yesterday, Tony Blair defended the government's decision to raise national insurance - and dismissed claims that the policy amounted to a broken promise.

Staking his career on the NHS investment agenda, the Labour leader said the plans were costed and could be funded without additional tax.

But he refused to "write the Budget" in advance.

He said that the increase in national insurance was supported by the "vast bulk" of middle England.

But he stressed that reform was essential and vowed to take on unions and interest groups if they stood in the way of change.

The first signs of post-Budget battles are set to emerge today when nurses demand a big rise in pay.

The Royal College of Nurses has revealed that it will consider strike action unless its members are given a bumper pay settlement.

The Conservatives said yesterday that they will vote against the NHS tax rises contained in last week's Budget.

Blair also revealed that he was still relishing the job of prime minister and signalled that he could go on "for years" to come.