'Thirty-five million people hear actor strangled on the air', scream the headlines. Radio producer Val Gielgud had the intriguing idea of making one of those quaintly melodramatic BBC murder mysteries the fulcrum for an archetypically English whodunit, with everyone apart from Sir Herbert Farquharson (homage to Sir John Reith!) likely suspects. This may be a low-budget quickie, but with efficient direction and a very knowledgeable script, the film becomes an evocative reminder of the seminal influence the BBC - with its Blattnerphones and sound-FX men and toffee-nosed producers - must have exercised on the cultural life of the 30s. You'll never guess whodunit, either.