MARK COLVIN: The Prime Minister has responded to a major report which says the war in Iraq has increased terrorism, by saying that terrorism existed long before the US and its allies overthrew Saddam Hussein.

The US National Intelligence Estimate, or NIE, is a joint document summing up the views of the CIA, the FBI, the Department of Homeland Security, the National Security Agency, and 12 other American intelligence agencies.

This year's NIE concludes that the war in Iraq has boosted Islamic radicalism.

The report directly contradicts assertions by US President George W. Bush that the war in Iraq has made the world safer...

Peter Bergen is an internationally respected expert on terrorism based at the New America Foundation and he explains the document's significance.

PETER BERGEN: What's really interesting here is that, you know, 16 separate US intelligence agencies have arrived at a consensus document. These National Intelligence Estimates are processes that can take can years, and this is not a conclusion that is arrived at lightly.

And the people who put together these kinds of assessments can hardly be described as sort of, flaming lefties, or you know, consistent critics of the Bush administration. I mean this is... these are career intelligence officers who have put together this assessment. And I think it's pretty devastating...

PETER BERGEN: You know, terrorism certainly existed before the Iraq war, but you know... so, on the other hand, the Iraq war has certainly sort of re-energised al-Qaeda and its affiliates.

Michael Scheuer, who is head of the bin Laden unit at CIA would say that, you know, if bin Laden believed in Christmas, the Iraq war would have been his Christmas gift...

For the complete interview, please visit the ABC Radio Australia website.