The Man Upstairs (1958) (UK-import)
Richard Attenborough stars as a scientist haunted by his past in this 1950s drama from director Don Chaffey. Trying to escape his guilt after accidentally killing his fiancee's brother, Peter Watson (Attenborough) changes his name and takes a rooms in a delapidated boarding house. There, his mental health rapidly deteriorates, and his fellow lodgers call the police after his erratic behaviour causes concern. But when Watson begins brandishing a gun, and a police sergeant is injured, matters quicky come to a head.