The film is a remake of a 1956 BBC serial called'My Friend Charles',& as such gallops thru the material in a relatively short time.I found it fast moving,enjoyable & unpretentious.Did anyone else notice the scenes,towards the end,where John Mills was being gassed?-the producers obviously decided to omit the scenes-maybe censorship?,but notice when he's sat by the window of the flat,deep breathing closely followed by similar scenes with the car window open. The Francis Durbridge serials all seemed to inhabit the same universe,that of unexplained happenings,people being not what they seem & the villain being someone close to the hero/victim.A predictable universe in some ways,but one with its own rules & regulations.