The Man Upstairs

Peter Watson (Richard Attenborough) lives in a dingy London boarding house, plagued by guilt and slowly losing his mind. His anguished state was caused by a terrible accident that occurred while Watson was working as a scientist, an accident that resulted in the death of his fiancé's brother. Unable to escape his depression, Watson's condition worsens. After causing a disturbance one night, a fellow tenant calls the police on him, which further unbalances his already precarious mental state.