Theophanous v Commonwealth of Australia

The High Court of Australia considered the case of *Theophanous v Commonwealth of Australia*, brought by the plaintiff, Mr. Theophanous, against the defendant, the Commonwealth of Australia. The dispute concerned the constitutional validity of certain provisions of the *Migration Act 1958* (Cth) and the *Migration Regulations 1994* (Cth), specifically those that allowed for the detention of non-citizens pending the determination of their immigration status. Mr. Theophanous, a non-citizen who had been detained under these provisions, challenged the lawfulness of his detention and the constitutional basis for such powers.

The central legal issue before the High Court was whether the provisions of the *Migration Act* and *Migration Regulations* authorising the detention of non-citizens for an indefinite period, or for a period exceeding that reasonably necessary to effect removal, were consistent with the implied constitutional prohibition against arbitrary detention. The Court was required to determine the scope of the executive power to detain non-citizens and whether this power was limited by the constitutional requirement for due process and the rule of law.

Crennan J, in his judgment, affirmed the principle that while the executive government has the power to detain non-citizens for the purpose of deportation, this power is not unlimited. His Honour reasoned that the detention must be for a purpose connected with the exercise of the immigration power and must not be arbitrary. The detention must be reasonably necessary for the purpose of effecting deportation or for other purposes prescribed by law that are incidental to the administration of immigration law. If detention extends beyond what is reasonably necessary for these purposes, it may infringe upon the implied constitutional prohibition against arbitrary detention, thereby rendering the relevant legislative provisions invalid.