Arrest powers where suspicion on reasonable grounds may be based on a mistake of law: Emde v State of New South Wales

The Court of Appeal referenced its previous judgment that “it is usually or generally only appropriate to grant leave of appeal concerning matters that involve issues of principle, questions of general public importance or a reasonably clear injustice going beyond something that is merely arguable…. [or] where there are substantial reasons to allow an appellate review… such as where there is an error of principle which, if uncorrected, will result in substantial injustice”.¹ 

The Court of Appeal considered that the matter may have raised questions of principle about the significance of ambiguity in an order the breach of which constitutes an offence, as well as whether reasonable grounds extend to matters involving errors of law. The Court also noted High Court authority on this question in the migration context which could be applied. It was on this basis that the Court examined the appellant’s arguments.

Emde submitted that the primary judge erred in finding that both constructions of the ADVO were reasonably available. Emde submitted there was only one objective construction of the order available to a reasonable person who had all the background knowledge which would have been available at the time, and thus, the s 99(1)(a) requirement of reasonable grounds could not be satisfied.

The Court of Appeal rejected the submission that the ADVO was not ambiguous and rejected the submission that any ambiguity in the ADVO was to be disregarded in the s 99(1)(a) analysis. The Court of Appeal noted that court orders should of course be unambiguous. However, the context in which the ambiguity was relevant was whether the statutory power of arrest of two officers in the field was engaged. Here, the orders were susceptible of more than one reasonable interpretation. The Court of Appeal determined that it was reasonable for the officers, in the circumstances where they were “required to make the assessment in real time with immediate consequences of acting or failing to act” (the primary judge at [74]) to suspect that the appellant had committed an offence.

The Court of Appeal noted that the matter raised an issue of principle about mistakes of law. If Emde’s construction of the ADVO was correct and the suspicion was based on a mistaken understanding of the law, could the officers’ suspicion still be based on reasonable grounds and thus authorized by s 99(1)(a)?

Prior to the hearing, the Court of Appeal drew the parties’ attention to two migration cases, Ruddock v Taylor² . and Thoms v Commonwealth³ . Both Ruddock and Thoms had a similar issue, and a similar power exercised by an officer: where decisions to cancel visas were quashed, could a belief or suspicion that detention was required which was based on a mistake of law be considered reasonable?

The High Court answered that question in the affirmative, stating in Ruddock that “what constitutes reasonable grounds for suspecting a person to be an unlawful non-citizen must be judged against what was known or reasonably capable of being known at the relevant time”.

Based on this reasoning, The Court of Appeal noted that it was arguable that what constitutes reasonable grounds for the 99(1)(a) suspicion – in the language of George v Rockett,⁴  “facts which are sufficient to induce that state of mind in a reasonable person” – is to be determined by reference to “what was known or reasonably capable of being known at the relevant time”.

The Court of Appeal considered that, if so, that may lend support to the approach the primary judge took to the ambiguity of the ADVO, and to the fact that the terms of the ADVO were conveyed over radio.

However, neither party made an argument on this point. Emde’s solicitor accepted that Ruddock and Thoms may be relevant to s 99 but made no submission. Senior Counsel for the State indicated he was unaware of any Court of Appeal decision attending to the question whether the High Court authorities were applicable to s 99, but that the issue was not one of public importance as there was no doubt that a mistake as to the construction of the order would not disentitle the officers from relying on s 99.

As the arguments were not made, the Court considered that it would be inappropriate to consider the point of principle further. In all, the Court refused leave to appeal.

This judgment leaves a question open about whether the High Court authority on reasonable suspicion in a migration and detention context could apply to the powers of arrest without warrant based on belief on reasonable grounds, particularly in situations involving ambiguity in court orders or legislation. Following the NSW Court of Appeal’s reasoning, it is open for future litigants to argue that reference to “what was known or reasonably capable of being known at the relevant time” could determine reasonable grounds for a suspicion that a person is committing or has committed an offence, thus enabling the power to arrest a person without a warrant.

Authors: Jeremy King and Isabella Jones