Scream And Scream Again (1970)

Starring Vincent Price, Christopher Lee, Peter Cushing, Judy Huxtable, Alfred Marks
Directed by Gordon Hessler
(actor & director credits courtesy IMDB.com)

While London police search for a killer who drinks the blood of his victims like a vampire, a mysterious operative uses murder to climb the ranks of a military government.

Despite some effective shocks, including a hospital patient waking up to discover his limbs are missing, and the presence of horror stars Price, Lee, and Cushing, this film's marred by a convoluted screenplay that fails to adequately explain a number of plot points.  Genre fans will also be disappointed that the three stars have no scenes together, save for a brief exchange between Lee and Price at film's end.  Director Hessler does stage some effective sequences, particularly a police chase of the "vampire" killer, but it's not enough to overcome the film's problems.