Tony Blair has pledged to stay on for a full third term if he wins the next general election.

His announcement on Thursday night was coupled with news that he will undergo further treatment for a heart condition.

Speaking to the BBC following the conclusion of the Labour conference and the close of polls in the Hartlepool by-election, Blair said he would not fight a fourth general election, and would stand down at the end of the next parliament.

"The decision as to who is the prime minister of the country is the decision of the British people - they're the boss," he said.

"But if I am elected I would serve a full third term. I do not want to serve a fourth term.

"I don't think the British people would want a prime minister to go on that long but I think it's sensible to make plain my intention now."

He added: "If you put yourself forward, you've got to put yourself forward for the full term."

The prime minister added he still had "something to give and contribute to the country".

"The point is, I still feel a sense of passion and conviction about what I do."

The Labour leader said that the door was still open for the chancellor to move from 11 Downing Street to Number 10.

"I don't think it rules Gordon out in any shape or form at all - he'd be younger than many prime ministers have been if he took over at the end of a third term," Blair said.