It’s all neatly sewn together and recalls the early Hitchcock spy chasers, The Lady Vanishes and the 39 Steps. The playing is fitted nicely to the director’s and writer’s specifications and there are some appealing portraits limned by Austrian actors.

Seventy years on such sombreness seems timely, as does Harry Lime, Welles's deliciously elusive antihero.

Krasker's camera reveals a dank, matte, defeated city - so dully vivid as to be a character unto itself - except that this Vienna becomes something altogether different seen at night or underground.

A chatty, propulsive mystery that still crackles with insouciant energy.