The prime minister has dismissed suggestions that the pressure of high office will force him to quit.

Addressing journalists Tony Blair signalled a determination to push on with his modernising agenda for the public services.

His remarks came after constitutional affairs secretary Lord Falconer said the prime minister would seek re-election and aim to govern for a full third term.

Declining to say whether Falconer's comments were accurate, Blair said there was "a big job of work still to do".

And he added that his "appetite for doing it is undiminished".

"But who the country elects is ultimately a matter for the country," he said.

On Saturday the government will become the longest serving Labour administration in British political history.

Analysts have suggested that the government's second term has lacked the radicalism and drive of its first four years.

But Blair said that the stresses and strains of the job would not prompt him to stand down.

The comments will be seen as a blow to chancellor Gordon Brown - who is still widely expected to succeed the prime minister.

Questioned on whether there were any comparisons with former England cricket captain Nasser Hussain - who stepped down saying he was tired and had run out of ideas - Blair said: "I think that captaining the England cricket team is probably a harder job."