Richard Perle is often referred to as the "high priest" or the godfather of neo-conservatives, although he is actually a conservative Democrat

He has also been called the "architect of the war", a claim he denies, and more critically "the prince of darkness".

Mr Perle, a good friend of the current defence secretary Donald Rumsfeld, recently resigned from the influential Defence Policy Board just before the war because of allegations about conflicts over his business interests.

He is also a member of the neo-conservative think tank, the American Enterprise Institute.

Prominence

Mr Perle studied politics at Princeton University before moving on to work for the hawkish conservative senator Scoop Jackson.

He then moved onto a post as assistant defence secretary in the Reagan era of the 1980s.

In the year 2000, Mr Perle rose to political prominence again after advising George W Bush's campaign on defence matters during the presidential campaign. He however declined a paid post in the administration.

Instead he took the unpaid chairmanship of the Defence Policy Board (DPB) instead.

Foothold

In the run-up to the war Richard Perle went on the offensive, making caustic remarks about the roles of US "allies" such as Saudi Arabia and France.

The DPB, created in 1985, has an advisory role and is not technically part of the Administration, however critics say it has gained a stronger foothold in shaping White House opinion in the past two years.

He resigned as chair of the DPB earlier in the year, although he is still on the board.