Plaintiff M68/2015 v Minister for Immigration and Border Protection & Ors; Plaintiff M80/2015 v Minister for Immigration and Border Protection & Ors

In two related proceedings, M68/2015 and M80/2015, the plaintiffs, identified as Plaintiff M68/2015 and Plaintiff M80/2015, brought actions against the Minister for Immigration and Border Protection and the Commonwealth of Australia, as well as Transfield Services (Australia) Pty Ltd. The core dispute concerned the lawfulness of certain conduct, including restraints on liberty, undertaken by the Commonwealth, allegedly through its contract with Transfield. The matters came before the High Court of Australia.

The primary legal issues before the Court included whether the plaintiffs had standing to seek declaratory relief concerning past conduct, and the validity of recently enacted amending legislation that purported to authorise executive restraint on liberty offshore. The plaintiffs contended that the amending legislation, despite its passage, was not supported by a head of Commonwealth power and therefore did not constitute the requisite authorisation for the conduct in question. They also raised arguments concerning the interpretation of the amending legislation and its interaction with existing legal principles, particularly in light of High Court decisions such as *Williams (No 1)* and *Williams (No 2)*.

The Court was required to consider the constitutional validity of the amending legislation, specifically whether it was supported by the aliens power or the external affairs power, and whether it was consistent with Chapter III of the Constitution. The defendants sought to strike out aspects of the plaintiffs' claims, particularly those seeking declarations about past conduct, arguing that such relief would not quell a real controversy as it would not ground any right to recompense or other legal right. The plaintiffs, however, maintained that their claims, including those relating to past conduct, remained valid and that the amending legislation did not resolve the fundamental questions about the lawfulness of the Transfield contract and the associated restraints on liberty.