First George was up against the right-wing fanaticism of McCarthyism in Good Night, and Good Luck. Then he had a pop at industrial oil giants in Syriana. Now he's waging war on America's dodgy petro-chemical industry.

Chemical leviathan U-North is one of those annoying multinational firms that plants a leaf/tree/flower on their company logo as a pretty desperate attempt to buy environmental credibility.

You can trust us, it seems to say. Come and let your kids play at one of our child-friendly refineries and we can guarantee any consumption of corrosive by-products will not result in a lingering death.

However, their eco-credentials are sliding down the pan after a class action suit is launched over claims the firm produced a carcinogenic weedkiller that did for a couple of hundred victims.

Glacial company litigator Karen Crowder (Swinton) is working alongside attorney Arthur Edens (Wilkinson) until the latter - a manic depressive - finds what he's being expected to do ethically incompatible with the truth.

Ripping his clothes off in court, however, is not the best way to undo the lethal machinations of a multi-national and his New York law firm's fixer Michael Clayton (Clooney) is sent to Milwaukee to mount a damage limitation exercise.

Unfortunately, George brings his own baggage...including a broken marriage, a failed restaurant venture and a gambling habit that has pushed him into debt and chains him like a convict to his firm.

As you might expect from the directorial debut of the screenwriter of the Bourne series, Tony Gilroy's invigorating thriller is at more pains than most to paint in a convincing backstory for the main protagonists.

Clooney doesn't stray far from the cool, urbane register we've come to expect and he's a commanding presence on screen, reining back from the self parody of Danny Ocean.

There are no surprises in a formulaic plot (which never really stands up to scrutiny) yet this is elevated a couple of notches by zinging dialogue and fleshed-out characters.

It's a cool, intelligent thriller and boasts a closing confrontation between Clooney and Swinton that is truly stand-out.

Tim Evans