Roy v O'Neill

The High Court of Australia considered an appeal by Ms Roy against a decision of the Northern Territory Court of Appeal. The dispute arose from a police attendance at Ms Roy's unit, where she was subject to a Domestic Violence Order (DVO). The police, engaged in a proactive policing operation, sought to check compliance with the DVO, which included a condition that Ms Roy not remain in her partner's presence while intoxicated. Following a knock on the door, Ms Roy was observed to be intoxicated, and a subsequent breath test indicated the presence of alcohol. Ms Roy was charged with breaching the DVO.

The central legal issues before the High Court were whether the evidence of the breath test was lawfully obtained and whether the police had trespassed on Ms Roy's property. Specifically, the court had to determine if a common law implied licence permitted the police to approach the unit and knock on the door, and whether their attendance at the unit was for a lawful purpose. The appellant contended that the police's purpose was solely to use coercive powers to obtain a breath sample, irrespective of her condition.

The High Court reasoned that the common law implies a licence for members of the public, including police, to approach a dwelling and knock for lawful purposes. This implied licence balances the occupier's right to privacy with the practicalities of social interaction and the need for lawful communication. The court found that Constable Elliott had a dual purpose in attending the unit: to check on Ms Roy's compliance with the DVO and, importantly, to ascertain the welfare of Mr Johnson, the protected person. This latter purpose was considered a lawful purpose sufficient to engage the implied licence. The court rejected the argument that the police's intention was solely to obtain a breath sample regardless of circumstances, finding instead that the intention to require a breath test was contingent on Ms Roy's condition.

The appeal was dismissed. The High Court upheld the decision of the Northern Territory Court of Appeal, finding that the police's attendance at the unit was lawful by reason of the common law implied licence, and that the evidence obtained from the breath test was therefore lawfully obtained.