Operation Mincemeat

This is not the first time the remarkable tale of how British intelligence service came to use a dead body in a bid to fool the Nazis has been brought to the screen - with Clifton Webb and Gloria Grahame's starrer The Man Who Never Was also giving it a noir-inflected go back in 1956.

This time out, it's Shakespeare In Love and Best Exotic Marigold Hotel director John Madden at the helm with a British cast as highly polished as an Admiralty house doorknob, including Colin Firth, Matthew Macfadyen, Kelly Macdonald, Penelope Wilton and Jason Isaacs. Michelle Ashford, who has mostly written for TV in the past, does an effective, if quite densely scripted, job of bringing Ben Macintyre's book to the screen as we see how naval officer Ewan Montagu (Firth) is seconded to intelligence alongside RAF lieutenant Charles Cholmondeley (Macfadyen) to hatch the elaborate "trojan horse" plot.

Montagu's marriage is in freefall, with his family recently departed to the States for safety, while Cholmondeley is a shy and nervous sort who is facing pressure from his bereaved mum to repatriate his brother's body from Chittagong and pressure from his superior Admiral Godfrey (Jason Isaacs) to dig dirt on Montagu's potentially Communist sympathising brother Ivor (Mark Gatiss).

Helping Montagu and Cholmondley to create a back story for the homeless man they are going to use as bait is Montagu's long-time secretary Hester (Penelope Wilton) and bright, youngish thing Jean (Macdonald), who soon finds herself attracting the stiff-upper lipped attentions of both men.

The central plot has an fittingly old fashioned sweep and suitably tense as it gradually unfolds, while Madden does good work to add movement to its stuffier, more expositional moments by using cutaways to visually tell the story rather than getting cooped up with those who are talking. Still, it feels a bit overburdened in places. The presence of writer Ian Fleming (Johnny Flynn) as a civil servant writing at his desk, offers some opportunities for humour regarding spycraft and the fact that all civil servants seem to be writing a book but his flowery narration also feels laboured and unnecessary given that the tale is perfectly able to speak for itself.

The cinematography in the ocean scenes also lacks the polish of the indoor scenes, with the heavy blue filter used giving them all the realism of a video game. The love triangle also plays second fiddle, so that despite the best efforts of Firth and Macdonald it never quite musters the heat or danger it should - in fact the most emotional moment courtesy of the fake love letter written by Hester, which acts as a gentle reminder of how much so many lost to war. Elegant and gripping but perhaps just a little genteel.