Screened at Sundance (Premieres). Dir: Michael Apted. UK. 2001. 117mins.

Revisiting a little-known yet extremely important and heroic chapter of World War II, Michael Apted's Enigma is a compelling, sumptuously-made romantic thriller that is effective in both its political and more personal dimensions. Steeped in the tense atmosphere of wartime Britain, this suspenseful drama centres on the mysteries of codes and code breaking, while at the same time telling a quintessentially noir tale of love, obsession and betrayal.

Theatrical prospects are excellent for an intelligent film that benefits from a bright and elegant screenplay by Oscar-winner Tom Stoppard, based on Robert Harris' bestselling novel; taut storytelling; luxuriant production values; and splendid acting by Kate Winslet, Jeremy Northam and, above all, Dougray Scott cast in a seductive role that might catapult him to international stardom. However, as a period piece with an extremely complicated, demanding and cerebral plot, Enigma is likely to appeal commercially to educated arthouse patrons seeking mature and provocative entertainment.

To describe nowadays a film as old-fashioned is also to pay it a compliment, for the gap between sophisticated technical values and intelligent and thoughtful storytelling has never been as wide as it is in mainstream Hollywood cinema. Enigma is unabashedly old-fashioned, not only in the kind of story that it tells, but also in the mode and visual style in which it is told. The film's richly-dense ambience, moral ambiguity and historical authenticity recall espionage films and books by John Le Carre and Graham Greene. Indeed, in its noir sensibility and period details Enigma brings to mind Neil Jordan's splendid adaptation of Greene's The End Of The Affair, which was set in the same period and also concerned a doomed love affair.

In March 1943, the code breakers at Bletchley Park, Britain's top secret Station X (situated 60 miles north of London), are facing their greatest challenge - and worst nightmare: Nazi U Boats have unexpectedly changed the codes by which they communicate with each other and the High Command. Almost reluctantly, the authorities turn for help to Tom Jericho (Scott), a brilliant young mathematician and code breaker who has recently experienced a mysterious nervous breakdown.

In a manner recalling forceful Hollywood thrillers, the tale's time frame is tight, actually four days, during which a brilliant team of scientists at Station X has to prevent a disaster of colossal proportions: an Allied merchant shipping convoy, which is crossing the Atlantic with 10,000 passengers and vital supplies, is in danger of a massive attack.

Rather shrewdly, scripter Stoppard has taken some liberties with the chronology of the source material to present a parallel personal tragedy, which makes Enigma a more emotionally stirring and accessible movie. Through flashbacks that are smoothly integrated into the text, Stoppard relates Tom's love affair with Claire, a beautiful blonde, very much in the tradition of film noir's femme fatales. Unknown to his already suspicious colleagues, Tom becomes obsessed by the unravelling of another, equally baffling enigma of his own: Claire's sudden disappearance from Bletchley just when the authorities begin to suspect that there may be a spy at Bletchley Park.

The achievement of Stoppard's taut and shapely narrative is that he not only establishes a causal link between the two enigmas, but he also implicates the viewers in deciphering a crime mystery in which the amorous Tom becomes prime suspect. The plot is far too complex and twisty to unravel here, suffice to say that the missing Claire was romantically and/or professionally involved with at least two other crucial figures.

Enter Wigram (Northam), a member of the secret service, who interrogates Tom about his relationship with Claire, showing too much interest in Tom's past. It becomes clear from their very first meeting that these two men are not only opponents, but are heading towards a showdown, which occurs in a masterly orchestrated last reel, set on a fast-moving train and in a seemingly pastoral village in Scotland, a place hinted at early on in a postcard Claire keeps on a wall.

Although very much a solitary, haunted noir hero, Tom soon bonds with Hester (Winslet), Claire's likeable roommate. Both girls work at Bletchley: Claire on the German book, filing transcripts of all decoded messages and Hester as a "blisterer" arranging intercepted ciphers. Together, Tom and Hester examine four sheets of original cryptograms found buried under the floor at Claire's cottage, soon realising that they are German army signals. Taking the documents from Bletchley is a severe act of treason, but undeterred, the duo resolves to use them to find Claire before the authorities realise that anything is wrong.

A number of elements contribute to Enigma's poignancy, elevating it way beyond the level of just a well-executed thriller. Based on fact, Enigma relates an almost obscure chapter in history, one that ultimately helped the Allies win the war. Furthermore, the central mystery is linked to a shameful, real-life scandal in WWII: a massacre of Polish soldiers by the Russian army, a disaster that was only recently acknowledged by the Russian government. On another level, younger, tech-oriented viewers will be intrigued by the film's setting: Station X can be perceived as the birthplace of the computer age.

A veteran feature and documentary helmer, Apted brings his entire experience (including the James Bond actioner The World Is Not Enough) to a film that represents his smoothest, most technically accomplished work to date, one that benefits immensely from his well-known attention to historical and anthropological detail.

Apted is no stranger to depicting bizarre communities and lifestyles (Coal Miner's Daughter, Gorillas In The Mist) and, indeed, one of Enigma's unexpected delights is his vivid portrait of Station X as a communal experience. In the film, it emerges as much more than a workplace, a site where eccentric geniuses, rigid military types and clever women of all classes co-existed, courted, and married - and in the process, unbeknownst to them, became reluctant heroes.

Enigma, the first production from Mick Jagger's Jagged Films (which is managed by Victoria Pearman), boasts technical sheen in each and every department: Seamus McGarvey's widescreen lensing is always well-composed, John Beard's production design is packed with rich period detail, Rick Shaine's editing is sharp and illuminating in its cross-cutting and montages, and John Barry's music is one of his most evocative and subtle scores in years. Each player of the central quartet, Scott, Winslet, Northam, and Burrows, gives a superlative, utterly credible performance.

Prod cos: Intermedia Films and Senator Entertainment presentation, in association with Meespierson Films CV, of a Jagged Films/Broadway Video Production. Exec prods: Victoria Pearman, Guy East, Nigel Sinclair, Hanno Huth, Michael White. Prods: Lorne Michael, Mick Jagger. Scr: Tom Stoppard, based on the novel by Robert Harris. Cinematographer: Seamus McGarvey. Prod des: John Beard. Ed: Rick Shaine. Music: John Barry. Main cast: Dougray Scott, Kate Winslet, Jeremy Northam, Saffron Burrows, Nikolaj Coster-Waldau, Corin Redgrave.