(1) No act of a person constitutes an offence if the act is done under duress by threat, unless the act constitutes murder or attempted murder.
(2) A person does an act under duress by threat if he or she does it because he or she knows or believes—
(a) that a threat has been made to cause death or serious injury to himself or herself or to another person he or she is bound to protect if the act is not done; and
(b) that the threat will be carried out immediately if he or she does not do the act or if not immediately before he or she or that other person can obtain any protection against the threat;
(c) that there is no other way of preventing the threat being carried out, and the threat is one which in all the circumstances he or she cannot reasonably be expected to resist.
(3) It is for the defendant to show that the reasons for his or her act is the knowledge or belief as is mentioned in subsection (2).
(4) This section does not apply to a person who knowingly and without reasonable excuse exposed himself or herself to such a risk; it is for him or her to show that he or she did not so expose himself or herself to such risk.