Section 320

any act or omission is charged against any person as an offence; and

it is given in evidence on the trial of such person for that offence that he was insane so as not to be responsible for his action at the time when the act was done or omission made, then if it appears to the Court before which such person is tried that he did the act or made the omission charged but was insane as aforesaid at the time when he did the act or made the omission, the Court shall make a special finding to the effect that the accused was guilty of the act or omission charged but was insane as aforesaid when he did the act or made the omission.