For a time in the late 1960s and early 70s, the area around Highgate cemetery in north London was believed to be terrorised by a vampire. There were sightings, exorcisms, illicit grave excavations and even some desecrations. At the frenzied height of the speculation, the local police force got involved. In real-life events that sound like the stuff of Hammer horror (indeed, the Christopher Lee and Peter Cushing Hammer horror film Dracula AD 1972 was apparently inspired by the incident), two men, David Farrant and Sean Manchester, got involved in hopes of solving the case. But rather than becoming a Holmes and Watson of the supernatural dimension, they embarked on a bitterly fought contest to be the first to vanquish the vampire, each undermining the other man’s authority along the way. A bitter contest … James Demain as Farringdon and Alexander Knott as Sheffield. Photograph: Charlie Flint Here, Patrick Sheffield (Alexander Knott) is a bishop in robes and cassock while Daniel Farringdon (James Demain) is a tobacconist by day and vampire hunter by night. Written …