Tony Blair has praised an "evolution" of American foreign policy as President Bush begins his second term.

In an interview with the Guardian newspaper the prime minister presented an optimistic view of how the Republican administration will interact with the world in the next four years.

With Bush taking the oath of office in Washington on Thursday, Blair said his recent conversations with the president had hinted at a change of view on US unilateralism.

"If you are in the position of trying to spread values - to give people greater freedom and democratic rights - it is better to try and do that with other countries," he said.

"Evolution comes from experience," Blair added. "In the end, we can take security and military measures against terrorism but... the best prospect of peaceful coexistence lies in the spread of democracy and human rights."

Blair also believes he can get the US onside with his own priorities for Britain's presidency of the G8 - Africa and climate change.

On these issues and the Israeli-Palestinian conflict he said: "It is possible to construct an international agenda that is more consensual, more multilateral than what has gone before."

Iran

The prime minister was tight lipped about possible US intervention in Iran.

While America has "what appears to be a harder position" than the EU, he said Bush has so far been content to let Europe take the lead.

Asked if British forces such as the SAS are in Iran, as US soldiers are reported to be, Blair said: "We never answer questions about special forces, but do not take that as an answer indicating an affirmative."

But he was resolute on the subject of Iraq. "I would take the same decision", he said.

The post-invasion period "has proved to be very tough... tougher than we anticipated" he conceded.

And he acknowledged again that it was a mistake to disband the Iraqi army.

"I've said before that I think, in retrospect ... the speed of de-Ba'athification and disbanding of forces was too great," he said.

But Blair claimed Bush was prepared to patch up his differences with "old Europe".

"It is significant, in my view, that he is coming to Europe as his first foreign visit," he said.

Constitution

On the coming battle to ratify the EU constitution in a referendum, Blair said he is prepared to take on the Murdoch press in debate.

"I'm not going to start personalising it because I don't think that's very sensible," he said. "[However] I will be arguing against anyone who's arguing for a no vote."

And he expressed his confidence that the "yes" campaign will win.

"I have a very great deal of confidence in the British people [being] sensible enough to realise that in this day and age, in the early 21st century, to give up a strong position in the world's largest economic market and strongest political union would be extremely foolish," he said.

Pointing to this week's unveiling of the Airbus super jumbo in Toulouse, a joint European project, he said Britain would suffer outside of the EU.

"You tell me if we'd be part of this if we were outside Europe - you know we wouldn't," he argued.