The defence of illegality is founded on the maxim that no court will lend its aid to a man who founds his cause of action upon an immoral or an illegal act. Whilst one might think this defence would be a rare beast to spot in the litigation wilds, it has been deployed, amongst other things, to resist enforcement of an undertaking as to damages (Servier v Apotex), to fend off a claim seeking payment for smuggled tea (Holman v Johnson) and to prevent a fraudster taking sole ownership of a property that was not, beneficially, hers (Tinsley v Milligan). The Supreme Court’s judgment in Lewis-Ranwell v G4S), which traverses the tumultuous history of the defence, is a guide to its scope and nature.

Relevant facts

The Claimant in Lewis-Ranwell alleged that the Defendants failed properly to assess his mental health, which led to him being released into the community in a psychotic state. In that state, he killed 3 people, seriously injured others and was detained. The Claimant was found not guilty of murder by reason of insanity. The Claimant sought damages against the Defendants including for psychiatric injury, loss of liberty and loss of earnings. Amongst other things, the Defendants relied on the defence of illegality.

The threshold question

The Supreme Court said it was appropriate to start by asking in what the circumstances the illegality defence would be engaged. Here, the Supreme Court cited the dicta of Lord Mansfield in Holman that the defence would be engaged not only by criminal, but by immoral or illegal acts.  Such acts were sufficient to engage the interests of the State or the public interest. However, recalling the judgment of Lord Toulson in Servier, the Supreme Court noted that, in deciding whether the defence was engaged in circumstances not directly covered by well-established authorities, it was right to proceed carefully on a case-by-case basis, considering the policies which underlie the broad principle.

The Supreme Court determined that the Claimant’s actions in killing others (even though he was not criminally responsible for his actions) constituted unlawful conduct sufficient to engage the illegality defence.

The Patel approach

Having surmounted the threshold, the Supreme Court referred to the 3-stage structured approach proffered by Lord Toulson in Patel v Mirza), which requires consideration of:

• • The underlying purpose of the prohibition which has been transgressed (in Henderson v Dorset Healthcare, Lord Hamblen noted that other general policy considerations that impact on the consistency of the law and the integrity of the legal system also fell to be taken into account at this stage).

• • Any other relevant public policies which may be rendered ineffective or less effective by denial of the claim.

• • In this respect, while not seeking to lay down a prescriptive or definitive list, Lord Toulson identified the seriousness of the conduct, its centrality, whether it was intentional and whether there was marked disparity in the parties’ respective culpability, as potentially relevant factors.

Applying the Patel approach, the Supreme Court found that:

• • The prohibition transgressed was that most fundamental injunction against the taking of human life. The law sought to protect the public and to deter unlawful killing. Although the Claimant was spared criminal responsibility for his conduct, the Supreme Court emphasised that his conduct was unlawful and deserved to be condemned. Finding that the underlying purpose of the prohibition transgressed would be enhanced by denial of the claim, the Supreme Court noted in particular that members of the public would be surprised and concerned if the Claimant could claim compensation (paid out of public funds) for the consequences of his wrongful act. 
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  • The policy considerations at stage (a) in favour of denying a civil claim, founded as they are on the need to maintain the integrity of the legal system, greatly outweighed those at stage (b) in favour of permitting a claim. 
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  • The case involved the brutal killing of 3 men. The conduct was central to all heads of loss claimed and the effective cause of such loss. In all the circumstances, denial of the claim would not be a disproportionate response to the illegality.