Facts and Judgment
R v Byrne (1960) 2 QB 396
The appellant murdered a young girl staying in a YWCA hostel. He then mutilated her body. He did so as he was suffering from irresistible impulses which he was unable to control.
"abnormality of mind" was wide enough to cover the mind's activities in all its aspects, including the ability to exercise will power to control physical acts in accordance with rational judgment. But "abnormality of mind" means a state of mind so different from that of ordinary human beings that a reasonable man would term it abnormal. He was thus allowed the defence to reduce the murder conviction to manslaughter.