In the 1890s, a cave-in trapped some workers toiling on an extension to the London underground railway and their cannibal descendants haunt the Piccadilly Line, picking off and eating the odd commuter.
Also known, aptly, as Raw Meat, this is one of the best of the contemporary-set British horrors, and competes with the stronger American movies with its very clever, gruesome premise, dollops of splatter, lots of cynicism and some nice, down-at-heel London locations.
Tea-drinking copper Pleasence, in the performance of a lifetime, is on the track of the killers, and has to cut through bureaucratic red tape to get there, while down in the tunnels the last of the monsters is eking out his pathetic, horrid leftover life, expressing himself through the only words he knows - "mind the doors".
Director Sherman also made the cloying New Seekers Coca Cola ads, and used his share of the fee from that to finance this gusty, gritty debut; sadly, his subsequent work - Poltergeist III, Wanted Dead Or Alive - did not fulfilled its promise.
It's difficult to watch this without thinking of recent events in London, but it is nonetheless a very inventive and effective thriller, with a fantastic turn from Pleasence.