Lord Parker, C.J in trying to define diminished responsibility/capacity stated:
“abnormality of the mind which has to be contrasted with the time honored expression in the maghten rules defect of reason; means a state of mind so different from that of ordinary human beings that the reasonable man would term it abnormal.
It appears to us to be wide enough to cover the mind’s activities in all its aspects, not only the perception of physical acts is right or wrong but also the ability to exercise will power to control physical acts in accordance with that rational judgement”
More on Diminished Responsibility
Diminished responsibility capacity under the criminal code is restricted to cases of homicide, whereas the defense of uncontrollable impulse is a general defense to all offences. From one point of view the provision relating to uncontrollable impulse under the criminal code is wider than the defense of diminished responsibility or capacity.
Under the 1957 Act, an accused person, who succeeds in establishing diminished responsibility will be convicted of the offence of man-slaughter even if the offence he committed would have been murder but for the defense, where as a person who succeeds in raising the defense of uncontrollable impulse under the code will be found to be legally insane and cannot be convicted of any offence. The penal code neither recognizes the defense of uncontrollable impulse nor diminished responsibility. The defense is recognized under the M’Naghten rule.