There’s no faulting the ambition, or the exuberance, of this spirited adaptation for the National, in association with Kneehigh Theatre, of Michael Powell and Emeric Pressburger’s 1946 movie which was part technical fantasia, part love story and part Shavian debate in a celestial court of law. It is just a little hard, sometimes, to see the point of it all.

Tom Morris and director Emma Rice have taken the outline of the story and reinvented the central image of the stairway to heaven as a mobile parabola resembling the London Eye. A fighter pilot, Peter Carter (Tristan Sturrock) has bailed out of his flaming aeroplane without a parachute after being talked into survival mode by a wireless operator, June (Lyndsey Marshal) on the ground.

In the film, Kim Hunter’s June was American and David Niven’s dashing pilot a true-blue smitten Briton whose affair somehow represented the Anglo-American alliance at the end of the war. Here, the liaison is purely romantic, and the whole production posted as a dream ticket to immortality, conceived by Carter lying in a coma and tickled into theatrical reality by the manic interventions of a Norwegian illusionist (Gisli Orn Gardarsson, co-founder of the Icelandic company Vesturport) and the urgent encouragement of his neurosurgeon (Douglas Hodge).

Marius Goring played an outrageous French aristocrat in the film, sent by heaven to get Carter and place him before the tribunal. The stylistic masterstroke was to have the real world presented in Technicolor, while heaven had to make do with black and white, presumably because the money had run out. Morris and Rice create a uniform phantasmagoric world of bicycling nurses – at one point pedalling upside down to reveal a frantic line of threshing thighs and white stockings – and pyjama-clad male hospital patients. The crash is signified by a flaming bucket, an image that is brilliantly replicated all over the stage in a finale evoking the destructive bombing of both Coventry and Dresden.

The action sags a little in the course of two-and-a-quarter uninterrupted hours, but there’s no question that customers in the continuing £10-a-ticket Travelex season will feel they have good value. The on-stage band led by composer Stu Barker provide some gorgeous, lilting tango music, and the ensemble dance sequences (staged by Rice with choreographer Debra Batton) are as delightful as they are surprising. The whole show is an ingenious deployment of resources that replaces the stark, stylish wittiness of the movie with a more all-purpose melancholic mood of pro-life, anti-war poeticism.

A small-scale 1994 King’s Head musical version by Thomas Morgan and Kevin Metchear made a virtue of trying to do the impossible, which is somehow more exciting as a theatrical tactic. But it is a measure of the audacity and confidence here that the flying rope tricks, the swinging bedsteads and the regulated ensemble work all come out of a well prepared dramatic context. And when we arrive in heaven, the lights come up on an audience ironically supposed to be asleep or half-dead.

Tristan Sturrock is a plucky, engaging Carter, while Craig Johnson chips in with a perky performance as his already deceased co-pilot Bob Trubshaw. Lyndsey Marshal is an affecting June and Douglas Hodge really does drive things along just as they seem to start stuttering.

- Michael Coveney