Richard Perle, a senior adviser to the US defence secretary, said the US had broken international law, blaming French reluctance to attack Iraq for leaving Washington with "no practical mechanism consistent with the rules of the UN for dealing with Saddam Hussein".

"I think in this case international law stood in the way of doing the right thing," said Perle in London in comments published by the British media on Thursday. "International law ... would have required us to leave Saddam Hussein alone."

Perle was speaking at an event organised by the Institute of Contemporary Arts in London on Wednesday.

The influential Pentagon official’s comments represent a clear break with official White House statements. President George Bush, presently on a state visit to the UK, has always insisted the war was legal either because of existing UN security council resolutions on Iraq or as an act of self-defence.

Bush’s main ally in the invasion of Iraq, UK Prime Minister Tony Blair, has always said existing UN resolutions legitimised the attack on Iraq.

Critics astonished

Antiwar campaigners told Aljazeera.net on Friday they were astonished by Perle’s admission.

"It’s an incredible admission that Bush and Blair’s war in Iraq is illegal," said Andrew Burgin, spokesman of the Stop the War Coalition in London. "It underlines everything we’ve said about the so-called war on terror being an illegal campaign."

Burgin said the recent bomb attacks in Istanbul showed the illegality of the Bush-Blair campaign was "fuelling the level of terror around the world".

A British lawyer and leftist politician who has frequently criticised Washington's foreign policy, Louise Christian, told Aljazeera.net she was "greatly concerned" by Perle's admission and its implicit disregard for international law.

Prince of Darkness

Dubbed the Prince of Darkness by his critics - and a few awed admirers - because of his powerful behind-the-scenes influence, Perle is a senior member of the Pentagon’s defence policy board, which advises the US Defence Secretary Donald Rumsfeld.

He resigned from the board's chairmanship amid controversy in March, however, after allegations of commercial conflict of interest.

Perle is also a key member of the Project for the New American Century, a rightwing think tank closely linked to the White House and credited with inspiring much of the Bush administration’s foreign policy.

He has been a hawkish advocate of projecting US power both diplomatically and militarily without the restraint of international bodies such as the UN.