Compared to many other rights in the Charter, s. 27(4) has a more clearly defined sphere of operation.

You will need to consider s. 27(4) if you are assessing legislation or developing a new policy that intends to create retrospective criminal offences.

If you are doing so, s. 27(4) will be relevant if the retrospective criminal offence is also a criminal offence in international law. It is these type of offences that can have a permissible retrospective operation. Criminal offences in international law include:

  • crimes against humanity;
  • war crimes;
  • the crime of piracy;
  • the crime of genocide.

Note that the following offences are regarded as war crimes in the Commonwealth Criminal Code Act 1995.

  • wilful killing;
  • torture;
  • inhuman treatment;
  • biological experiments;
  • wilfully causing great suffering;
  • taking hostages; and
  • denying a fair trial.

This list is not exhaustive.

You should also consider s. 27(4) in a situation where legislation or policy expressly refers to international criminal law or international obligations in the creation of an offence.