Steve Punt turns private investigator, examining little mysteries that amuse and beguile. This week our detective
has to get to the bottom of whether the British inventor of a 'Death Ray' was really science fact or science fiction. His leads take him via the valleys of South Wales, the control tower of Croydon Airport, the banks of the River Severn and the strong rooms of records offices piecing together the remarkable story of Harry Grindell Matthews.

Grindell Matthews, maverick scientist and showman entrepreneur, earned many friends and was celebrated for inventions which included mobile phones, talking pictures and remote control craft; yet all of these were overshadowed once he unveiled his 'Death Ray'. Designed to shoot down enemy aircraft in the 1920's, his lastest creation earned headlines around the world but also stirred controversy. He fell foul of the establishment and withdrew to a mountain laboratory, closely monitored by the government. As an inter-war arms and technology race developed what was to happen to Grindell Matthews and his secret weapon: the infamous death ray?

Producer: Neil McCarthy. Show less