Section 4

Nothing is an offence which is done by a person who is, or who, by reason of a mistake of fact and not by reason of a mistake of law, in good faith believes himself to be, bound by law to do it.

A., an officer of a Court, being ordered by that Court to arrest Y., and, after due enquiry, believing Z. to be Y., arrests Z. A. has committed no offence.

Act of Judge when acting judicially.