Miller v Miller [2011] HCA 9

The High Court has found that (pursuant to s8 of The Criminal Code (WA)) a participant in a joint illegal enterprise can be owed a duty of care if, prior to the accident, they withdrew from the illegal enterprise. The fact that a plaintiff was involved in a joint illegal enterprise does not automatically mean that no duty of care arises. The existence of a duty of care is dependent upon on the relevant legislation that governs the illegal acts.


The 16 year old plaintiff had been drinking and wandering the streets of a Perth suburb with her sister and cousins. She had no money to get home and the last train had left, so she decided to steal a car. She managed to start a car in a nightclub car park. The defendant, aged 27, offered to drive the plaintiff and, her cousin and sister home. He got into the driver's seat and several of his friends also got into the car, totaling nine passengers. Initially the defendant drove safely, but then began to drive dangerously. The plaintiff twice asked to be let out; the defendant refused her requests. The car struck a pole, killing one passenger and injuring the plaintiff, leaving her a quadriplegic.

The Court was asked to only decide one aspect of the plaintiff's claim: whether the defendant owed the plaintiff a duty of care by reason of the fact that the plaintiff and the defendant were involved in a joint illegal enterprise at the time of the accident, namely, the unlawful use of the motor vehicle in question, without the owner's consent?

At first instance

The District Court of Western Australia considered this case did not fall into the same category as some of the other cases dealing with illegal joint enterprises and stolen cars, such as Smith v Jenkins, Gala v Preston and Kickett v SGIC, in which the Courts held that there was no duty of care.

The main distinguishing feature identified was that although this case involved a ride in a stolen car, it was not a 'joy-ride' and it was not a journey that courted the risk of serious injury, at least not from the outset. The fact that the motor vehicle was stolen 'was not a factor from which certain risks arose which would have made it impossible or not feasible to determine an appropriate standard of care.' The evidence did not reveal that the duty of care ordinarily owed by a driver of a motor vehicle to a passenger 'did not exist or should be attenuated.' Accordingly, the defendant was found to owe the plaintiff the usual duty of care that a driver owes a passenger.

Court of Appeal of the Supreme Court of Western Australia

The defendant appealed the decision on the ground that the District Court erred in law in finding that the defendant owed the plaintiff 'the usual duty of care that a driver owes a passenger', notwithstanding that the plaintiff and the defendant were involved in a joint illegal enterprise. The Court of Appeal held that in jointly using the stolen car, the plaintiff and the defendant together contravened s371A of The Criminal Code (WA) (now repealed) and accordingly, the defendant owed the plaintiff no duty of care as she was engaged in an illegal enterprise.

High Court of Australia

The Court considered the previous case law gave rise to the following propositions:

  • 'First, the fact that a plaintiff was acting illegally when injured as a result of the defendant's negligence is not determinative of whether a duty of care is owed
  • Second, the fact that plaintiff and defendant were both acting illegally when the plaintiff suffered injuries of which the defendant's negligence was a cause and which would not have been suffered but for the plaintiff's participation in the illegal act is not determinative
  • Third, there are cases where the parties' joint participation in illegal conduct should preclude a plaintiff recovering damages for negligence from the defendant
  • Fourth, different bases have been said to found the denial of recovery in some, but not all, cases of joint illegal enterprise
  • Fifth, the different bases for denial of liability all rest on a policy judgment.'

The High Court held that whether the engagement in a joint illegal enterprise negates the existence of a duty of care between participants depends on the statutory purposes of the section creating the offence. The statutory purposes of s371A of the Code were not consistent with a finding of duty of care between those who joined in committing the crime. However, consideration was also given to s8 of the Code which provided that jointly illegal tortfeasors will both be guilty of any offence, unless one of those persons withdraws from the prosecution by words or conduct accompanied by reasonable steps to prevent the commission of the offence. It was further noted that the purpose of s317A encompassed not only the protection of property rights, but also road safety and the prevention of dangerous driving.

The majority held that the plaintiff withdrew from the joint illegal enterprise when she asked to be let out of the car. As the defendant denied her requests, there were no reasonable steps then available to her to prevent the further commission of the offence. Accordingly, at the time of the accident she was no longer a party to the illegal enterprise and as such she was owed a duty of care by the defendant.


The High Court in Miller considered that reference must be given 'to the relevant statute, and identification of its purposes' when determining the issue of duty of care in relation to joint illegal tortfeasers. Whether there is a duty of care owed by a driver to a passenger in a joint illegal enterprise will depend on the particular legislation which governs the illegal enterprise within the particular state or territory.

There is however, no principle that denies a duty of care to a plaintiff, where that plaintiff was engaged in an illegal act.

In NSW, s54(2) of the Civil Liability Act 2002 potentially weakens the defence of joint illegal enterprise as the defence does not apply if the conduct of the defendant also amounted to an offence. As such, the section arguably permits recovery by plaintiffs who on common law grounds may well have failed.

Given the current law and the attitude of the High Court, the prospects of successfully defending a claim by alleging a joint illegal enterprise, appears to have been significantly reduced.

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