If you are developing a policy or legislation that will establish a retrospective criminal offence you should check whether the act is an offence under international law. You may wish to rely on this exception on retrospective criminal laws. You should pay particular attention to the elements of the offences. Ensure that the elements of the offences are consistent with those that apply in respect of the international law counterpart offence. (Consult Part 2 of the Rome Statute of the International Criminal Court for the elements of offences.)