Law of Torts Complete LLB Notes
Illegality as a Defence in Tort Law
Illegality as a Defence in Tort Law is an important topic under General Defences in the Law of Torts and is specifically included in the Rajasthan LL.B. syllabus along with Volenti Non Fit Injuria, Act of God, Inevitable Accident, Act of Third Parties, Novus Actus Interveniens, Plaintiff’s Wrong or Default, Self-Defence, Necessity, Statutory Authority, Judicial and Quasi-Judicial Acts, Parental and Quasi-Parental Authorities, and Mistake of Fact.
The defence is traditionally associated with the Latin maxim:
Ex turpi causa non oritur actio
It broadly means that a person should not ordinarily obtain a legal remedy from a cause of action arising out of his or her own illegal or seriously wrongful conduct.
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However, this does not mean that every unlawful act by a claimant automatically defeats a tort claim. Modern courts apply the doctrine carefully, with particular attention to public policy, the connection between the illegality and the claim, and proportionality.
1. Meaning of Illegality as a Defence
Illegality means unlawful conduct by the claimant which is sufficiently connected with the claim that allowing the claimant to recover would conflict with the law or public policy.
The doctrine is also referred to as:
- Illegality defence
- Ex turpi causa defence
- Ex turpi causa non oritur actio
- Illegality in tort
- Illegality as a defence to civil claims
The fundamental idea is that the court should not assist a claimant in obtaining a benefit from his or her own serious wrongdoing.
The doctrine is based on public policy rather than simply on fairness between the individual parties. Indian courts have similarly explained that the rule exists because courts should not lend their assistance to a claimant whose cause of action is founded upon an illegal or immoral act. (Indian Kanoon)
2. The Maxim: Ex Turpi Causa Non Oritur Actio
The maxim ex turpi causa non oritur actio is traditionally translated as:
No action arises from a dishonourable or illegal cause.
It is closely associated with the classic English decision of Holman v Johnson (1775).
Lord Mansfield explained the public-policy basis of the rule: the court does not refuse relief merely to benefit the defendant; rather, the court refuses to assist a claimant whose claim is founded upon an illegal or immoral act.
Indian courts have repeatedly referred to this principle. In Babulal Swarupchand Shah v South Satara, the Bombay High Court discussed the rule and quoted the principle from Holman v Johnson. (Indian Kanoon)
3. Is Illegality a Complete Defence in Tort Law?
Not automatically.
“Whenever the plaintiff has committed an illegal act, the defendant is not liable.”
The court must examine:
- What unlawful conduct did the claimant commit?
- Was the conduct sufficiently serious to engage the doctrine?
- How closely was the illegality connected with the claim?
- Would allowing the claim undermine the law or public policy?
- Would denying the claim be proportionate?
Modern English law has moved away from an overly mechanical application of illegality. The Supreme Court’s decision in Patel v Mirza established a policy-based framework, and the Supreme Court reaffirmed the importance of that framework in Lewis-Ranwell v G4S Health Services Ltd in 2026. (Supreme Court UK)
4. Holman v Johnson — Historical Foundation
Holman v Johnson (1775) 1 Cowp 341
This is the classic historical authority for the principle of ex turpi causa.
Facts
The claimant had sold goods to the defendant knowing that the goods were intended to be smuggled into England.
The claimant later sought payment.
Principle
Lord Mansfield stated that courts will not lend their assistance to a claimant whose cause of action is founded upon an illegal or immoral act.
Importance
The case established the public-policy foundation of the illegality doctrine.
Indian courts have also relied upon Holman v Johnson when explaining ex turpi causa. (Indian Kanoon)
Exam point
Holman v Johnson → historical foundation of ex turpi causa.
5. Illegality and Tort Claims
Although Holman v Johnson was not itself a tort case, the principle has subsequently been applied to tort claims.
The Court of Appeal expressly recognised in Pitts v Hunt that an illegality defence can be raised in an action founded in tort.
Therefore:
Ex turpi causa is not confined exclusively to contract law. It can operate in appropriate tort claims as well.
But its application in tort requires careful consideration of the relationship between:
the claimant’s unlawful conduct
and
the tort claim being brought.
6. Pitts v Hunt — Illegality in Tort
Pitts v Hunt [1991] 1 QB 24
This is an important case for understanding illegality in tort.
Facts
The claimant was a passenger on a motorcycle driven by the defendant.
The claimant knew that the defendant was:
- uninsured;
- unlicensed; and
- intoxicated.
The claimant also encouraged the defendant to drive recklessly.
The defendant subsequently died and the claimant suffered serious injuries.
The claimant brought a negligence claim against the defendant’s estate.
Decision
The Court of Appeal upheld the dismissal of the claim.
The judges approached the issue somewhat differently, but the case is a significant authority demonstrating that serious participation in a joint criminal enterprise can prevent recovery in tort.
Principle
Where the claimant’s unlawful conduct is sufficiently connected with the circumstances giving rise to the claim, illegality may operate as a defence.
Importance
Pitts v Hunt → serious joint illegal enterprise + tort claim.
7. Revill v Newbery — An Important Limitation
Revill v Newbery [1996] QB 567
This case is extremely important because it demonstrates that a claimant’s criminal conduct does not automatically make him an “outlaw” with no legal rights.
Facts
The claimant was a burglar who entered the defendant’s allotment shed.
The defendant, who was elderly, fired a shotgun through the shed door.
The claimant was injured.
The defendant argued, among other things, that the claimant’s illegal conduct barred his claim.
Decision
The Court of Appeal rejected the complete illegality defence.
The claimant’s criminal conduct did not give the defendant an unrestricted right to use dangerous force against him.
The court instead considered the defendant’s duty and the claimant’s conduct in determining liability and contributory negligence.
Principle
A person engaged in criminal conduct does not automatically lose all protection of the civil law.
This is an important qualification to Pitts v Hunt.
Exam point
Revill v Newbery → illegality is not an automatic or universal defence.
8. Why Revill v Newbery Is Important
Suppose:
- A trespasses onto B’s property to commit a crime.
- B responds with excessive or unreasonable force.
- A suffers injury.
B cannot simply argue:
“A was committing a crime, therefore I have no liability.”
The court must consider the nature of the defendant’s conduct and the legal duty owed to the claimant.
The Court of Appeal specifically rejected the idea that a criminal trespasser becomes an “outlaw” who can never recover compensation.
9. Illegality and Contributory Negligence Are Different
Illegality
May completely bar a claim where the doctrine applies.
Contributory Negligence
Generally involves apportionment of responsibility and reduction of damages according to the claimant’s contribution to the harm.
Revill v Newbery is a good illustration of why these doctrines should not be treated as interchangeable. The court rejected a complete illegality bar but considered the claimant’s conduct in relation to contributory negligence.
10. Modern Approach: Patel v Mirza
Patel v Mirza [2016] UKSC 42
This is one of the most important modern authorities on the illegality doctrine.
Although Patel v Mirza arose in a different civil context rather than being a straightforward tort case, its policy framework has become highly important in modern discussions of illegality. The UK Supreme Court considered whether denying relief was justified by the public policies underlying the illegality doctrine.
The court identified three important considerations:
1. Purpose of the prohibition
What is the purpose of the law that the claimant has breached?
Would denying the claim further that purpose?
2. Other relevant public policies
Would allowing or denying the claim support or undermine other important public policies?
3. Proportionality
Would denying the claimant’s legal remedy be a proportionate response to the illegality?
The Supreme Court formulated these considerations as a framework for determining whether public policy requires denial of relief.
11. Lewis-Ranwell v G4S Health Services Ltd — 2026 Development
Lewis-Ranwell v G4S Health Services (UK) Ltd [2026] UKSC 2
The UK Supreme Court decided the case on 21 January 2026.
The case concerned a negligence claim arising from killings committed by a claimant who had been found not guilty by reason of insanity.
The defendants argued that the claimant’s civil negligence claim was barred by illegality.
Supreme Court decision
The Supreme Court unanimously held that the claimant was barred by the doctrine of illegality from recovering compensation in negligence for the consequences of the killings.
The Court emphasised that:
- trivial unlawfulness should not automatically trigger the defence;
- the unlawful conduct must engage the public interest;
- the underlying rationale includes maintaining the coherence and integrity of the legal system;
- the court should apply the three-stage considerations from Patel v Mirza; and
- proportionality remains important. (Supreme Court UK)
Why is this case important?
It demonstrates that the modern illegality defence is not simply a rigid application of the Latin maxim.
Instead, courts examine:
public interest + connection + policy + proportionality
before deciding whether a claim should be barred.
12. The Three-Stage Modern Test
Based on the modern approach, students can remember:
Stage 1 — Purpose of the Prohibition
Ask:
What legal rule has the claimant violated, and would denying the claim further the purpose of that rule?
Stage 2 — Other Public Policies
Ask:
Would allowing or denying the claim affect another important public policy?
Stage 3 — Proportionality
Ask:
Is denying the claim a proportionate response to the claimant’s unlawful conduct?
This framework was expressly applied in Lewis-Ranwell in 2026. (Supreme Court UK)
13. Indian Position
The principle of ex turpi causa is recognised in Indian jurisprudence.
Indian courts have repeatedly stated that a court will not assist a claimant whose claim is founded upon an illegal or immoral act.
Babulal Swarupchand Shah v South Satara
The Bombay High Court discussed the principle that a court will not lend assistance to a person whose cause of action arises from an illegal or immoral act. (Indian Kanoon)
Kuju Collieries Ltd v Jharkhand Mines Ltd
The Supreme Court explained the principle of ex turpi causa non oritur actio, observing that a person cannot ordinarily claim a right or remedy founded upon an illegal transaction. (Indian Kanoon)
The Court also recognised that the application of the principle can involve well-recognised exceptions. (Indian Kanoon)
14. Chhanga Lal v MCD
Chhanga Lal v Municipal Corporation of Delhi
The Delhi High Court explained that the ex turpi causa defence rests upon public policy.
The court identified circumstances in which the defence may prima facie succeed, including situations where:
- the claimant’s case depends upon an illegal transaction;
- granting relief would enable the claimant to benefit from criminal conduct; or
- the circumstances otherwise fall within the underlying public-policy principle.
The court also emphasised that the defence should be applied pragmatically and cautiously. (Indian Kanoon)
This is particularly useful for explaining the Indian approach to students.
15. Illegality Does Not Automatically Mean No Remedy
This is a crucial examination point.
A claimant’s unlawful conduct may be:
A. Directly connected with the cause of action
The illegality may bar the claim.
B. Merely incidental to the claim
The claim may still succeed.
C. Relevant to contributory negligence
The claimant’s conduct may reduce damages rather than completely bar the claim.
D. Too remote or insufficiently serious
The illegality defence may not apply.
Therefore, the court must examine the connection between the illegality and the claim.
16. Illegality and Public Policy
The doctrine is fundamentally concerned with public policy.
The objective is not simply:
“The defendant should win because the claimant behaved badly.”
Instead, the question is:
Would granting the claimant a remedy undermine the integrity, coherence or policy of the legal system?
The modern Supreme Court approach places particular emphasis on this idea.
17. Illegality vs Volenti Non Fit Injuria
These are different defences.
| Illegality | Volenti Non Fit Injuria |
| Based primarily on public policy | Based on voluntary assumption of risk/consent |
| Concerned with claimant’s unlawful conduct | Concerned with claimant’s voluntary acceptance of risk |
| May completely bar a claim | May completely bar liability where requirements are satisfied |
| Ex turpi causa | Volenti non fit injuria |
| Focuses on integrity/policy of legal system | Focuses on consent and assumption of risk |
18. Illegality vs Plaintiff’s Default
Plaintiff’s Default
The claimant’s own wrongful conduct contributes to the circumstances giving rise to the claim.
Illegality
The claimant’s conduct is sufficiently unlawful and connected with the claim to engage the public-policy doctrine.
A plaintiff’s wrongful conduct does not automatically amount to illegality.
19. Illegality vs Contributory Negligence
Contributory Negligence
Generally concerns the claimant’s lack of reasonable care and can lead to reduction of damages.
Illegality
May result in complete denial of a claim where the doctrine applies.
But in some cases, conduct that might otherwise be relevant to illegality can instead be dealt with through ordinary principles such as contributory negligence.
Revill v Newbery demonstrates this distinction particularly well.
20. Important Cases on Illegality in Tort Law
| Case | Principle / Importance |
| Holman v Johnson (1775) | Historical foundation of ex turpi causa |
| Pitts v Hunt (1991) | Illegality can operate in tort where claim is sufficiently connected with serious unlawful conduct |
| Revill v Newbery (1996) | Criminal conduct by claimant does not automatically bar tort recovery |
| Gray v Thames Trains Ltd (2009) | Important modern authority concerning illegality and consequences of criminal conduct |
| Patel v Mirza (2016) | Modern policy-based framework: purpose, other public policies, proportionality |
| Lewis-Ranwell v G4S (2026) | Recent Supreme Court application of the modern illegality framework in a negligence claim |
| Kuju Collieries Ltd v Jharkhand Mines Ltd (1965) | Indian Supreme Court authority on ex turpi causa |
| Babulal Swarupchand Shah v South Satara (1959) | Indian authority explaining the public-policy basis of the doctrine |
| Chhanga Lal v MCD (2008) | Indian authority emphasising cautious and pragmatic application |
The Indian authorities support the proposition that courts will not ordinarily assist a claimant whose claim is founded upon illegality, while also recognising that the doctrine must be applied according to its purpose and circumstances. (Indian Kanoon)
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21. Exam-Oriented Rule
Illegality is a public-policy doctrine under which a claimant may be denied a civil remedy where the claim is sufficiently connected with the claimant’s own illegal or seriously wrongful conduct and granting relief would undermine the integrity or policy of the legal system. However, illegality is not an automatic defence merely because the claimant has acted unlawfully; the court must consider the nature and connection of the unlawful conduct and, under the modern approach, relevant public policies and proportionality.
22. Conclusion
Illegality as a Defence in Tort Law is based on the principle of ex turpi causa non oritur actio. Historically, courts refused to assist a claimant whose cause of action arose from an illegal or immoral act.
However, modern tort law does not apply the doctrine mechanically.
Cases such as Pitts v Hunt demonstrate that serious participation in an illegal enterprise can bar recovery, while Revill v Newbery demonstrates that unlawful conduct does not automatically deprive a claimant of all civil protection.
The modern approach focuses on public policy, the purpose of the prohibition, consistency of the legal system and proportionality. This approach was developed in Patel v Mirza and has been applied in the tort context by the UK Supreme Court in Lewis-Ranwell v G4S Health Services Ltd (2026).
In one line:
Illegality may defeat a tort claim when the claimant’s unlawful conduct is sufficiently connected with the claim and allowing recovery would conflict with important public-policy considerations, but illegality is not an automatic defence to every tort claim.
FAQs — Illegality as a Defence in Tort Law
1. What is illegality as a defence in tort law?
Illegality is a public-policy defence under which a claimant may be denied relief when the claim is sufficiently connected with the claimant’s own illegal or seriously wrongful conduct.
2. What is the meaning of ex turpi causa non oritur actio?
Ex turpi causa non oritur actio means that a legal action should not ordinarily arise from an illegal or dishonourable cause. It expresses the principle that courts should not assist a claimant in obtaining relief from his or her own serious wrongdoing.
3. Is illegality a complete defence in tort law?
Not automatically. The court examines the nature of the illegality, its connection with the claim, relevant public policies and whether denying the claim would be proportionate.
4. What is the leading case on illegality as a defence in tort?
Pitts v Hunt [1991] 1 QB 24 is an important English tort authority demonstrating that serious participation in a joint illegal enterprise may prevent recovery. Revill v Newbery is equally important as a limitation because it shows that criminal conduct does not automatically eliminate a claimant’s civil rights.
5. What is the modern test for the illegality defence?
The modern approach considers the purpose of the prohibition breached, other relevant public policies, and whether denying the claim would be proportionate. This framework is associated with Patel v Mirza and was applied by the UK Supreme Court in Lewis-Ranwell v G4S (2026).
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