The prime minister will tonight strongly defend his close relationship with President Bush.

Tony Blair will use a speech at Mansion House to address concerns that he has become too closely involved in the Bush administration's aggressive foreign policy.

He will insist that Bush's promotion of democracy abroad is also a "progressive left" agenda.

Blair will also say that public opinion in Iraq is strongly behind a new democratic state.

In an interview with America's NBC television, the prime minister asked: "Where would we be as Britain or as Europe if America disengaged from the world and said: 'You guys go and sort out all the problems in the world'?

"I think we get an enormous amount out of this relationship because we believe in the same things, we share the same interests."

He added: "When people say: 'Where is your payback from this relationship?' my answer is: My payback is the relationship."