The first film on which Frank Launder and Sidney Gilliat shared a screenplay credit, Seven Sinners (d. Albert de Courville, 1936) is a breezily unpretentious comedy-thriller that amply demonstrates their skill at constructing a commercially winning package while still displaying enough wit and individuality to continue entertaining audiences seven decades later.
The idea behind the Arnold Ridley and Bernard Merivale stage hit The Wrecker (1928), in which a man deliberately crashes trains in order to prove the superiority of buses, was fused with stylistic ingredients from recent Hitchcock hits The Man Who Knew Too Much (1934) and The 39 Steps (1935). American actors Edmund Lowe and Constance Cummings were cast in the leads and the opening scenes were set during the Nice Carnival in the South of France to give the film international appeal, a policy that producer Michael Balcon was pursuing across Gaumont-British studios at the time.
Launder and Gilliat handle the convoluted plot competently enough, but the film's real strengths, as so often in their work, lie in the witty repartee between Harwood (Lowe) and Fenton (Cummings). Equally typically, the film works in contemporary references - the scenes with the Pilgrims of Peace movement would certainly have had resonance at a time when Hitler was a growing threat in Germany.
Much of the train footage was recycled from Geza von Bolvary's silent adaptation of The Wrecker (1928), and though the joins and models reveal themselves occasionally, there are moments that are startlingly effective - one shot of a steam train falling over on its side appears to be genuine. It certainly trumps Hitchcock's notoriously unconvincing model work in The Lady Vanishes (1938), which Launder and Gilliat wrote for him a couple of years later, in the process recycling the winning formula of trains, spies and mysterious disappearances one more time.