Critical reception of The Fallen Idol was good when it opened as a film in London. Greene’s writing had transposed sympathetically to the screen, and Ralph Richardson was memorable as the genial if adulterous butler Baines. The story touched on Greene’s personal anxiety about the ‘green baize door’. His father had been headmaster of a public school in Berkhamsted near London, and each day as a young boy Greene would experience a conflict of loyalties as he left the family quarters to enter the pupils’ world. Frontiers have a dynamism of their own in Greene’s fiction: they set off a reflex of unease.

As a Jewish refugee with his own experience of betrayal in Fascist Hungary, Korda was impressed by the out-takes he had seen of The Fallen Idol. Now he wanted Greene to write an original screenplay for a film to be set in bomb-shattered Vienna. The city would make a good setting for a thriller, Korda believed. Virtually every Viennese was involved in black-marketeering of one kind or another; there was not merely defeat in the former Nazi outpost, but debasement. Greene mentioned to Korda the germ of his tale about the ‘risen-from-the-dead’ Harry Lime. Korda was taken with the idea, and a few days later he agreed to act as backer.

In early February 1948 Greene left London for the ‘smashed, dreary city of Vienna’. The Austrian capital was divided into four occupied zones – Russian, American, French, British – and everywhere Greene went he saw evidence of the moral and material ruins of Hitler’s collapsed empire. Some families were still camped out with their children, competing with the rats for food and shelter. Vienna offered as sad a spectacle as Sarajevo or Baghdad would to a later generation, and Greene brings the city to life in his descriptions of the destroyed baroque elegance along the Danube and the ‘great wounded spire’ of St Stephanskirche. Kim Philby’s old channels of pursuit and escape – the Vienna sewers – had become an international no-man’s-land where criminals like Harry Lime could move about unchecked by the city’s quadripartite control.2