With her chameleon-like qualities as an actress, it only seems natural that Cate Blanchett should shine playing someone who's not what she seems.

We first met her properly as the compulsive gambler in Oscar and Lucinda, then she took on the crown of Elizabeth and last time out she was ethereal Galadriel in Lord of the Rings.

This time round she's Charlotte Gray, a determined Scotswoman recruited to the Special Operations Executive during World War II.

She's trained to act as a courier in Vichy, that part of France which is openly collaborating.

But she has an ulterior motive - her RAF pilot lover Peter (Rupert Penry-Jones) has been shot down - and she sets off to get to him behind the backs of her colleagues.

Communist resistance fighter Julien (Billy Crudup) finds her a home with his estranged father Levade (Michael Gambon) - and two Jewish boys whose parents have been seized by gendarmes.

It's a small town where duplicity is commonplace - no-one trusts the Nazis, most are suspicious of the Vichy regime yet many are united by a lingering anti-Semitism.

Just to make things awkward, the tide of the war is turning and London is already preparing for a world untainted by the political ideals of Moscow.

When Charlotte learns that Peter is dead, she focuses her mind on saving the Jewish youngsters - but is their cover blown?

Together with the impressive Enigma, British film-makers appear to have discovered a genre where their skills can thrive.

Director Gillian Armstrong has created an austere, bleakly threatening atmosphere against which Blanchett discovers humanity's highs and lows.

Blanchett is effervescent in a highly satisfying thriller, even if the departures from Sebastian Faulk's novel may not please everyone.

Tim Evans