This crime thriller was made towards the end of the German "Edgar Wallace" movie series, which lasted from 1958 until 1972. Cult sleaze director Jess Franco got "Edgar Wallace"-regulars Siegfried Schürenberg and Horst Tappert for this one, but obviously the quite well known actors swallowed up the whole budget: The film itself is very cheap.
Although the movie takes place in London, most of the film was made in Spain. Therefore, all cars are driven on the right side of the street and the streets look typically spanish... yeah, heck, who will spot the difference to London?
Aside from the low production values, the whole story is an incoherent mess. The motivations of most of the characters (especially Horst Tappert's) remain unclear, and there are enough scenes that appear useless to the plot. The whole thing is so trashy it has to be seen to be believed.
In the end, exactly all the flaws make this cinematic catastrophe very entertaining and funny. A good party tape, but certainly not typical Jess Franco stuff. By the way: Horst Tappert went on to play the character "Inspector Derrick" for the German TV-crime-series "Derrick" (1974-1998) and became the best known cable policeman in the history of German television.