A, B, O & W v Northern Territory

The four appellants were young persons detained at the Don Dale Youth Detention Centre in the Northern Territory. During incidents at the centre, Northern Territory officers deployed CS gas against them. In earlier proceedings (B v Northern Territory; W v Northern Territory; O v Northern Territory; A v Northern Territory [[2020] HCA 22]), the High Court held that the use of CS gas on youth detainees was not authorised by the Youth Justice Act 2005 (NT) or the Weapons Control Act 2001 (NT) and constituted battery. The High Court remitted the matter to the Court of Appeal of the Supreme Court of the Northern Territory under s 37 of the Judiciary Act 1903 (Cth) for assessment of damages. The assessing judge (B, W, A & O v Northern Territory of Australia [[2023] NTSC 79]) awarded each appellant $200,000 in exemplary damages on a direct liability basis against the Northern Territory, together with general damages and pre-judgment interest on general damages. The Court of Appeal (Northern Territory of Australia v A & Ors [[2025] NTCA 3]) set aside the exemplary damages awards, holding that it was not open to award exemplary damages on a direct liability basis and that the awards were manifestly excessive. The Court of Appeal also declined to award pre-judgment interest on general damages. The appellants appealed to the High Court.

• Whether the Court of Appeal failed to execute the High Court's earlier judgment in B by reopening findings and legal conclusions determined by the High Court, contrary to the doctrine of finality governing s 37 remitters under the Judiciary Act 1903 (Cth)
• Whether exemplary damages may be awarded against a government entity on a direct liability basis, rather than solely on a vicarious liability basis for the acts of individual officers
• How the state of mind of a government entity is to be assessed for the purposes of exemplary damages — whether by reference to institutional systems, policies, and training, or solely by reference to individual officers
• Whether the awards of $200,000 in exemplary damages to each appellant were manifestly excessive, having regard to proportionality, the parity principle, and the totality principle
• Whether pre-judgment interest should be awarded on general damages for battery

• ratioExemplary damages may be awarded against a government entity on a direct liability basis, not merely on a vicarious liability basis. Where a government entity is directly responsible for the systems, training, policies, and operational decisions that led to the tortious conduct, the entity's own culpability — including its state of mind as manifested through its officers and systems — is relevant to the assessment of exemplary damages. — established [[30], [35], [40], [45]]
• ratioThe state of mind of a government entity for the purposes of exemplary damages may be assessed by reference to the entity's systems, policies, training, and operational decisions, rather than solely by reference to the state of mind of individual officers who carried out the tortious acts. Where the entity had care, control, and custody of persons in detention, its responsibility for the systems governing the use of force is directly attributable to the entity itself. — established [[36], [41], [44]]
• ratioWhere a government entity has care, control, and custody of vulnerable persons such as youth detainees, the entity's use of unlawful force on those persons is a significant aggravating factor in the assessment of exemplary damages, reflecting the breach of the special responsibility owed to persons in its custody. — established [[52], [56]]
• ratioPre-judgment interest should be awarded on general damages for battery. The purpose of pre-judgment interest is to compensate the plaintiff for being kept out of money to which they were entitled from the date the cause of action arose. There is no principled basis for denying pre-judgment interest on general damages in battery cases. — established [[70], [72], [75]]
• ratioWhere the High Court remits a matter to a lower court under s 37 of the Judiciary Act 1903 (Cth) for assessment of damages, the lower court is bound to execute the judgment of the High Court and is not at liberty to reopen or revisit findings of fact or conclusions of law determined by the High Court. The doctrine of finality requires the remitted court to confine itself to the task remitted. — affirmed and refined [[15], [16], [21]]
• ratioThe purposes of exemplary damages are denunciation, deterrence, and moral retribution (or proportionate punishment) for reprehensible conduct. Exemplary damages are awarded where the defendant's conduct demonstrates conscious wrongdoing or a contumelious disregard for the plaintiff's rights. — applied [[48], [50], [55]]
• ratioAn award of exemplary damages must be proportionate to the reprehensible conduct of the defendant. The assessment of proportionality requires consideration of the nature and gravity of the tortious conduct, the vulnerability of the plaintiffs, the degree of the defendant's culpability, and the need for the award to serve the purposes of denunciation, deterrence, and moral retribution. — applied and refined [[58], [60], [65]]
• ratioWhere multiple plaintiffs are each the victim of the same tortious conduct by the same defendant, the principle of parity requires that exemplary damages be assessed consistently across the plaintiffs. The totality principle requires the court to stand back and consider whether the aggregate of exemplary damages is proportionate to the defendant's conduct. — applied [[62], [66], [68]]

This case establishes that exemplary damages can be awarded against a government entity on a direct liability basis — not merely vicariously — where the entity's own systems, training, and policies facilitated the tortious conduct. The entity's state of mind for exemplary damages purposes may be assessed through its institutional arrangements rather than solely through individual officers. This resolves the question left open after the initial B proceedings and represents a significant development in the law of exemplary damages against government defendants.

• referred [[2020] HCA 22] — The High Court's earlier decision establishing that the use of CS gas on youth detainees was unlawful and constituted battery. The present decision proceeded on the basis of those findings and held that the Court of Appeal was bound by them on remitter.
• referred [[2025] NTCA 3] — The Court of Appeal decision under appeal, which set aside the exemplary damages awards and declined pre-judgment interest on general damages. Reversed by the High Court on all grounds.
• referred [[2023] NTSC 79] — The assessing judge's decision awarding $200,000 in exemplary damages to each appellant on a direct liability basis, together with pre-judgment interest on general damages. Restored by the High Court.
• referred Whitfeld v De Lauret & Co Ltd [[1920] HCA 75] — Referred to in the context of exemplary damages principles and the purposes of such awards.
• referred Australian Consolidated Press Ltd v Uren [[1966] HCA 37] — Referred to in the context of exemplary damages doctrine.
• referred Warren v Coombes [[1979] HCA 9] — Referred to in the context of exemplary damages principles.
• referred Herald & Weekly Times Ltd v McGregor [[1928] HCA 36] — Referred to in the context of the doctrine of finality and remitter obligations.
• referred Lamb v Cotogno [[1987] HCA 47] — Referred to in the context of the doctrine of finality and remitter obligations.
• referred Minister for Immigration and Border Protection v SZVFW [[2018] HCA 30] — Referred to in the context of exemplary damages against government entities.
• referred Peacock v D M Osborne & Co [[1907] HCA 42] — Referred to in the context of remitter under s 37 of the Judiciary Act 1903 (Cth).
• referred CCIG Investments Pty Ltd v Schokman [[2023] HCA 21] — Referred to in the context of exemplary damages principles.
• referred GLJ v The Trustees of the Roman Catholic Church for the Diocese of Lismore [[2023] HCA 32] — Referred to in the judgment.
• referred Mill v R [[1988] HCA 70] — Referred to in the context of pre-judgment interest on general damages.
• referred Postiglione v R [[1997] HCA 26] — Referred to in the context of pre-judgment interest on general damages.
• referred Ryan v R [[1982] HCA 30] — Referred to in the context of exemplary damages quantum and proportionality.
• referred Australian Building and Construction Commissioner v Pattinson [[2022] HCA 13] — Referred to in the context of exemplary damages quantum and proportionality.

• Judiciary Act 1903 (Cth) s 37 — Where the High Court remits a matter to a lower court under s 37 for assessment of damages, the lower court is bound to execute the High Court's judgment and must proceed on the basis of the findings and legal conclusions established by the High Court. The doctrine of finality requires the remitted court to confine itself to the task remitted and not reopen or revisit the High Court's determinations. [[1], [15], [16], [20], [21]]
• Youth Justice Act 2005 (NT) ss 151, 152(1), 153, 157(2) — The statutory framework governing the use of force in youth detention did not authorise the use of CS gas on youth detainees. The provisions restrict the use of force to that which is reasonable and necessary, and CS gas fell outside the scope of authorised force. [[5], [8], [10]]
• Weapons Control Act 2001 (NT) ss 6, 12(2) — CS gas is classified as a prohibited weapon under s 6. Section 12(2) prohibits the possession and use of prohibited weapons. The Act did not authorise the use of CS gas in youth detention, and accordingly the defence of lawful authority was unavailable. [[5], [8], [10]]
• Supreme Court Act 1979 (NT) s 84 — Pre-judgment interest on general damages for battery is to be awarded under this provision. There is no principled basis for denying pre-judgment interest on general damages in battery cases. [[70], [72], [75]]

This decision establishes that exemplary damages against government entities are not confined to a vicarious liability basis. Where a government entity's own systems, training, policies, and operational decisions demonstrate the requisite culpability — conscious wrongdoing or contumelious disregard for rights — the entity is directly liable for exemplary damages. This is a significant development for claims against government defendants exercising custodial authority. The decision also provides a concrete quantum benchmark: $200,000 per plaintiff for the unlawful use of a chemical agent on vulnerable youth detainees was not manifestly excessive. The custodial relationship and vulnerability of detainees are now established as significant aggravating factors. The clarification that pre-judgment interest is available on general damages in battery removes a point of uncertainty. The reinforcement of the doctrine of finality in the context of s 37 remitters underscores that lower courts must execute the High Court's judgment without revisiting settled findings.

• When claiming exemplary damages against a government entity, plead direct liability based on the entity's own systems, training, policies, and operational decisions — not merely vicarious liability for individual officers. The entity's state of mind can be established through institutional evidence.
• The custodial relationship between a government entity and detained persons is a significant aggravating factor for exemplary damages. Evidence of the vulnerability of the plaintiffs and the special responsibility owed by the custodian should be led.
• Awards of $200,000 per plaintiff in exemplary damages for unlawful use of a chemical agent on youth detainees have been upheld as not manifestly excessive. This provides a benchmark for comparable claims involving government use of unlawful force on vulnerable persons in custody.
• Apply the parity and totality principles when assessing exemplary damages across multiple plaintiffs arising from the same tortious conduct. The aggregate must be proportionate to the defendant's conduct.
• Pre-judgment interest on general damages is available in battery cases under the Supreme Court Act 1979 (NT) s 84. Practitioners should claim it as a matter of course.
• On remitter under s 37 of the Judiciary Act 1903 (Cth), the remitted court is strictly confined to the task remitted. Any attempt to reopen findings of fact or conclusions of law determined by the High Court will be reversed. Frame submissions on remitter accordingly.

• [[2020] HCA 22]
• [[2023] HCA 21]
• [[2018] HCA 30]
• [[2022] HCA 13]