Damon and Greengrass team up once more for an intelligent thriller set in Baghdad, writes MARK LUNDRIGAN

BOURNE is back. Well, it's Miller this time actually, but Matt Damon and director Paul Greengrass's reunion has more than a whiff of similarity to the successful spy trilogy - which is no bad thing. OK, so Damon knows who he is this time - he even has his name, Chief Warrant Officer Roy Miller, emblazoned on his uniform as if to ram that difference home.

But again, he is searching for the truth (do weapons of mass destruction exist in Iraq?); again, there are shady Americans running corrupt intelligence departments; and again, he is a highly-trained soldier who can and will kill (but now he knows it).

The first time we see Miller, he is in the Green Zone (an area in central Baghdad taken over by American troops in 2003 and where a succession of Iraqi regimes were based) searching for weapons of mass destruction, using intelligence provided by a 'reliable' source.

But after the search leads Miller and his troops to a disused toilet factory rather than missiles, he begins to question the intelligence provided - and whether the source actually exists.

Pentagon officials, led by slimy intelligence officer Clark Poundstone (Greg Kinnear), swat away Miller's claims that there are no WMD, but the CIA's Baghdad bureau chief Gordon Brown (Brendan Gleeson) has long suspected the absence of any WMD and helps Miller with an undercover investigation.

Based on a book by journalist Rajiv Chandrasekaran, Imperial Life In The Emerald City, the film throws up more questions than answers, but then that's the point - will we ever know the truth?

Damon is as reliable as ever in the role of accidental hero, leading us through shootouts and explosions, despite President George W Bush at the film's start declaring 'the war is over'.

Kinnear also shines as the shady Poundstone, willing to do anything to cover up the fact that no weapons can be found, and that the invasion was therefore unnecessary.

There is also a delightful, if fleeting, evil performance by Jason Isaacs as Major Briggs, an American military officer under the command of Poundstone, who is commanded to stand in the way of Miller's investigations.

Unfortunately, the shaky camerawork distracts from the storyline.

Headache-inducing hand-held cameras used in every scene lend the film a documentary-style effect, but it's far too over the top (in one chase scene, the camera is thrown about so much that everything is just a blur).

There are also underused characters such as Wall Street Journal reporter Amy Ryan, but then this is Damon's film.

As for Greengrass, his decision to show America's willingness to fight internally despite 'the war being over' should have high-ranking officers at the Pentagon hiding behind their desks, and has provided more than enough to satisfy Bourne fans who are praying for a fourth installment.