Illegality and public policy

Illegality is the point at which contract law refuses to carry out its ordinary office. The usual questions in this paper are whether an agreement was formed, what it meant, whether consent was defective, and what remedies follow from breach. Illegality asks a prior and more disquieting question: even if ordinary contract doctrine would otherwise assist the claimant, should the court withhold its assistance because the transaction, purpose, performance, or claim is tainted by law-breaking or by a policy which the legal system must not undermine?

The modern law is dominated by Patel v Mirza [2016] UKSC 42. Before Patel, English law was often presented through maxims and mechanical tests: ex turpi causa non oritur actio, no cause of action arises from a disgraceful cause; and the reliance test associated with Tinsley v Milligan [1994] 1 AC 340. Patel replaced that formal approach, at least for most civil claims, with a structured assessment of policy and proportionality. The court considers: first, the underlying purpose of the rule which has been transgressed and whether denying the claim would further that purpose; secondly, any other relevant public policy which denial would affect; and thirdly, whether denial would be a proportionate response to the illegality.

For Part IB Contract, the practical significance is twofold. First, illegality is not one doctrine but a cluster of rules and policies: contracts prohibited by statute; contracts to commit crimes, torts or frauds; contracts performed illegally; claims for restitution after a failed illegal transaction; and contracts void or limited because they offend public policy, especially unreasonable restraints of trade. Secondly, the topic is highly examinable because it brings together formation, interpretation, statutory construction, unjust enrichment and remedial discretion. It rewards candidates who do not treat illegality as a moral slogan.

A Cambridge answer should be organised by the source and location of the illegality. Ask: what is unlawful or objectionable; is the contract itself prohibited, or merely the mode of performance; is the claimant suing on the contract, claiming restitution, or invoking a property right; what policy is served by denying or allowing relief; and is the proposed outcome proportionate? Most weak answers jump directly to ex turpi causa or recite Patel as a three-part incantation. Strong answers identify the legal source of the prohibition and then show how the modern doctrine mediates between deterrence, coherence, non-profiting from wrong, protection of vulnerable parties, and avoidance of unjust windfalls.

The central tension is institutional. Courts must not enforce arrangements which subvert statutes or the administration of justice. But overbroad illegality rules may themselves damage the legal system: they can confer arbitrary windfalls, punish beyond the scheme chosen by Parliament, and leave exploited parties without redress. Patel is best understood as an attempt to replace categorical forfeiture with principled judicial control. Whether it succeeds is the principal academic and examination issue.

The classical starting point is Lord Mansfield's judgment in Holman v Johnson (1775) 1 Cowp 341. The case concerned the sale of tea by a seller in Dunkirk to a buyer who intended to smuggle it into England. The seller could recover the price because he had not participated in the unlawful smuggling. The famous proposition was not that courts punish immorality as such, but that they will not assist a claimant who must found the claim on his own illegal act. The maxim was judicial self-restraint dressed as moral principle: the court withheld its process to avoid complicity in illegality.

Nineteenth- and early twentieth-century law divided public policy into categories. Some contracts were illegal because prohibited by statute. Others were unenforceable because contrary to common law public policy: agreements to commit crimes or torts, agreements prejudicial to the administration of justice, agreements tending to corruption in public life, certain contracts associated with sexual immorality, and unreasonable restraints of trade. The categories were sometimes treated as closed or at least cautiously extended, because public policy was regarded as an unruly horse. Yet courts necessarily continued to decide which policies were sufficiently fundamental to defeat private bargains.

The older law was also shaped by formal distinctions between voidness, unenforceability and restitution. If a statute expressly prohibited a contract, the matter was comparatively easy. More difficult were statutes which created offences or regulatory duties but did not state the private-law consequence. St John Shipping Corporation v Joseph Rank Ltd [1957] 1 QB 267 is the classic warning against assuming that every statutory breach invalidates the contract. A shipowner overloaded a ship contrary to statute but could still recover freight: the statute imposed penal consequences but did not intend to deprive the carrier of contractual payment. This approach recognises that contract law must not add sanctions which Parliament has not chosen unless necessary to give effect to the statutory purpose.

In the late twentieth century, illegality became heavily influenced by the reliance principle. In Tinsley v Milligan [1994] 1 AC 340, two women bought a house in one name to facilitate benefit fraud. The claimant nevertheless established a beneficial interest because she could rely on a resulting trust without pleading the illegal purpose. The outcome turned not on the seriousness of the illegality but on whether the claimant needed to rely on it to make out the cause of action. The rule was praised for certainty but criticised for arbitrariness. A slightly different pleading route could determine whether a party lost a home.

The pressure for reform came from several directions. In tort, cases such as Gray v Thames Trains Ltd [2009] UKHL 33 and Hounga v Allen [2014] UKSC 47 showed a more policy-sensitive approach. In unjust enrichment and contract, the House of Lords and Supreme Court confronted the inadequacy of rigid reliance rules. The decisive break came in Patel v Mirza, where money paid for an intended insider-dealing arrangement was recoverable after the unlawful purpose was not carried out. Lord Toulson, for the majority, treated illegality as a doctrine concerned with the integrity of the legal system, not with technical pleading. That formulation has since governed most private-law illegality analysis, although its open-textured character remains controversial.

This history matters for Cambridge examinations because older cases have not disappeared. They provide the categories, examples and statutory-construction instincts through which Patel must operate. Patel does not mean that all illegal transactions are now enforceable if the judge feels sympathy. Nor does it abolish specific statutory consequences. It supplies a framework for deciding whether denial of relief is justified where the law is otherwise indeterminate.

1. Begin with the source of the illegality. The first question is not whether the claimant is morally unattractive. It is whether there is a legal norm which the transaction, purpose, performance or claim would contravene. That norm may be statutory, criminal, tortious, regulatory, equitable, fiduciary, or a common law public policy. A contract to pay a bribe, to commit a fraud, or to stifle a prosecution is different from a lawful contract performed in a manner involving a collateral statutory breach.

1. Distinguish illegal formation, illegal purpose and illegal performance. A contract may be illegal as made: for example, a bargain whose object is criminal conduct or corruption. It may be lawful on its face but entered into for an illegal purpose known to both parties. It may be lawful as made but performed illegally by one party. The consequences vary. Where the contract's very object is prohibited, enforcement will normally be denied. Where illegality lies only in performance, courts ask whether the statute or policy requires non-enforcement, having regard to seriousness, knowledge, centrality and purpose.

1. Statute is primary. If legislation expressly states the civil consequence, the court applies it. Gambling provides an example of legislative reversal of older policy: the fact that a contract relates to gambling no longer prevents enforcement. Competition legislation may render anti-competitive arrangements prohibited. Regulatory statutes may impose licensing requirements, criminal penalties or administrative sanctions. Where the statute is silent, the court asks whether invalidity is necessary to promote the statutory purpose. St John Shipping shows that it often is not. A court should be slow to superadd civil forfeiture where Parliament has calibrated the sanction.

1. Patel v Mirza supplies the modern general test. The court assesses whether allowing the claim would damage the integrity of the legal system. The three considerations are: the purpose of the transgressed prohibition; other relevant public policies; and proportionality. This is not a free discretion to do justice in the individual case. It is a structured evaluation of legal policy. Relevant proportionality factors may include the seriousness of the conduct, whether it was intentional, whether denying relief would be a deterrent, whether denial would be disproportionate punishment, whether the parties were equally culpable, and whether refusal would confer an unjust windfall.

The landmark cases show the movement from categorical maxims to policy-sensitive analysis. Holman v Johnson supplies the classical maxim. Its importance is often misunderstood. Lord Mansfield was not saying that courts exist to punish all moral fault. He was identifying the impropriety of allowing a claimant to found an action on his own unlawful conduct. The seller in Holman recovered because the illegal smuggling was the buyer's purpose and not part of the seller's pleaded claim.

Nordenfelt v Maxim Nordenfelt Guns and Ammunition Co Ltd is the foundation of the restraint of trade doctrine. The House of Lords accepted that restraints are not automatically void, but they must be justified. A covenant given on the sale of a business may be wider than one in employment because the purchaser pays for goodwill and needs protection against its immediate destruction by the seller. The case establishes the structure still used today: legitimate interest, reasonableness between the parties, and consistency with the public interest.

St John Shipping is indispensable for statutory illegality. Devlin J refused to treat every statutory breach as invalidating contractual rights. The decision forces candidates to ask what consequence Parliament intended. It also anticipates the proportionality concerns later explicit in Patel: denial of freight would have been a severe additional sanction for a regulatory breach already penalised by statute.

Tinsley v Milligan represents the high-water mark of formalism. The claimant's beneficial interest survived because she did not need to rely on the fraudulent purpose to establish the resulting trust. The case was defensible as certain and rule-like, but it produced arbitrary distinctions. A claimant's fate could turn on pleadings rather than on the policy of the law infringed, the parties' culpability, or the remedy sought.

Patel v Mirza is the modern pivot. The claimant paid money to the defendant for a proposed insider-dealing scheme which was not carried out. He recovered the money. The Supreme Court rejected the reliance test as the governing principle and asked whether allowing recovery would harm the integrity of the legal system. Restitution prevented an unjust enrichment and did not enforce the illegal bargain. The decision is not a universal permission to unwind illegal contracts; it is a framework for deciding when refusal of relief is justified.

Hounga v Allen, though not a contract case in the narrow sense, is important because it shows how public policy can cut both ways. A domestic worker employed unlawfully because of immigration status brought a race discrimination claim. The Supreme Court permitted the claim, giving weight to policies against trafficking and discrimination. The case is useful in contract essays to show why illegality doctrine cannot be reduced to deterrence.

Tillman v Egon Zehnder is the leading modern severance case in restraint of trade. The Supreme Court allowed severance of words which made a covenant too wide, provided the removal did not require adding to or modifying the remaining wording and did not generate a major change in the overall effect of the restraint. It confirms that restraint of trade remains a specialised public-policy doctrine with its own techniques, even after Patel.

See practice questions section below.

See further reading section below.