Liyanage and others v The Queen [1967] 1 AC 259

The parliament of Ceylon made a law that retrospectively created new crimes so as to punish those who attempted a coup d’etat, saying it worked retrospectively and that it would cease to function as a law once court proceedings ended against the perpetrators of the coup d’etat.

This act legalised holding Defendants without warrant for arrest or trial for longer than the period allowed by law, altered the law of evidence so as to ensure their conviction and made admissible to the court statements made by them that would normally have been inadmissible AND it specified what punishments should be given to them.

The Privy council (NB NOT binding on UK courts) rejected the argument that Defendants should be acquitted on grounds of natural justice but did quash the convictions because the act of the Ceylon parliament usurped the judicial function of the courts, making a law specifically for punishing Defendants, and thus breaching the separation of powers which was enshrined under the constitution of Ceylon.