Learning Outcomes
After reading this article, you will be able to explain the illegality defence in negligence, including its rationale, the ex turpi causa maxim, and the modern approach following Patel v Mirza. You will be able to identify when the defence applies, analyse key case scenarios, and apply the correct legal principles to SQE1-style problem questions.
SQE1 Syllabus
For SQE1, you are required to understand the operation and limits of the illegality defence in negligence. You must be able to identify when the defence may apply, explain the relevant policy considerations, and apply the correct legal test to factual scenarios.
As you revise this article, focus on:
- the meaning and effect of the ex turpi causa non oritur actio maxim
- the public policy justifications for the illegality defence
- the three-stage test from Patel v Mirza and its application to negligence claims
- the requirement for a close connection between the illegality and the claim
- how the defence is treated in key cases and typical exam scenarios
Test Your Knowledge
Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.
- What is the effect of a successful defence of illegality (ex turpi causa non oritur actio) in a negligence claim?
- Which case established the current three-stage test for the application of the illegality defence in civil claims?
- In which of the following situations is the illegality defence most likely to succeed? a) A claimant injured while committing a burglary sues the property owner for negligence. b) An undocumented worker injured at work sues their employer for unsafe conditions. c) A passenger not wearing a seatbelt sues a negligent driver.
- What are the three main factors a court must consider under the Patel v Mirza test?
Introduction
The illegality defence, known by the Latin maxim ex turpi causa non oritur actio, is a complete defence to a negligence claim in certain circumstances. If successful, it prevents a claimant from recovering damages where the claim is closely connected to the claimant’s own illegal or seriously immoral conduct. This defence is rooted in public policy and aims to protect the integrity of the legal system.
Key Term: ex turpi causa non oritur actio The Latin maxim meaning "no action arises from a dishonourable cause." It bars a claim where the claimant must rely on their own illegal or seriously immoral act.
The rationale for the illegality defence
The illegality defence is based on several public policy reasons:
- The courts should not assist a claimant to profit from their own wrongdoing.
- The law should not condone or encourage illegal conduct.
- Civil remedies should not undermine criminal sanctions.
- The integrity of the legal system must be maintained.
Key Term: public policy The principle that courts may refuse to enforce rights or claims if doing so would harm the public interest or the integrity of the legal system.
The modern approach: Patel v Mirza
The Supreme Court in Patel v Mirza [2016] UKSC 42 set out the current approach to the illegality defence in civil claims, including negligence. The court rejected rigid rules and instead adopted a flexible, policy-based test.
Key Term: Patel v Mirza test The three-stage approach requiring courts to consider: (1) the purpose of the law breached, (2) any other relevant public policies, and (3) whether denying the claim would be a proportionate response.
The three-stage test
When deciding whether to apply the illegality defence, the court must consider:
- The purpose of the legal prohibition: Would denying the claim strengthen or undermine the purpose of the law that was broken?
- Other relevant public policies: Are there competing policies (such as the need to compensate victims or prevent unjust enrichment) that should be weighed?
- Proportionality: Is denying the claim a proportionate response, considering the seriousness of the illegality, its centrality to the claim, and whether it was intentional?
When does the defence apply?
The defence is not engaged by every unlawful act. The key question is whether there is a sufficiently close connection between the claimant’s illegal conduct and the claim. The more direct the link, the more likely the defence will succeed.
Key Term: close connection The requirement that the claimant’s illegal conduct must be sufficiently linked to the claim for the defence to apply.
Examples of application
- The defence is likely to succeed where the claimant seeks compensation for harm suffered while jointly committing a serious crime (e.g., burglary, violent crime).
- The defence is unlikely to succeed where the illegality is incidental or unrelated to the harm (e.g., an undocumented worker injured due to employer negligence).
Worked Example 1.1
Scenario:
Ben and Carl jointly steal a car. Carl drives recklessly and crashes, injuring Ben. Ben sues Carl for negligence.
Answer: The illegality defence will succeed. Ben’s claim arises directly from their joint criminal enterprise. Allowing the claim would undermine public policy and the integrity of the legal system.
Worked Example 1.2
Scenario:
Maria is working illegally in the UK. She is injured at work due to her employer’s failure to provide safety equipment. Maria sues her employer for negligence.
Answer: The illegality defence is unlikely to succeed. Maria’s illegal status is not central to the employer’s breach of duty. Public policy favours workplace safety and does not justify denying her claim.
Key cases and exam scenarios
- Pitts v Hunt [1991] 1 QB 24: Claimant injured while participating in a joint illegal activity (joyriding). Claim failed due to the close connection between the illegality and the claim.
- Revill v Newbery [1996] QB 567: Burglar injured by excessive force from property owner. Claim succeeded because denying all claims would be disproportionate and contrary to the policy of protecting life.
- Hounga v Allen [2014] UKSC 47: Undocumented worker allowed to claim for discrimination despite her illegal status, as public policy against trafficking and exploitation outweighed the illegality.
Exam Warning
The illegality defence is a complete defence. If successful, the claimant’s entire claim fails and no damages are awarded, regardless of the defendant’s fault.
Revision Tip
For SQE1, focus on the Patel v Mirza test and the need for a close connection between the illegality and the claim. Not every unlawful act will bar a negligence claim.
Key Point Checklist
This article has covered the following key knowledge points:
- The illegality defence (ex turpi causa non oritur actio) is a complete defence to negligence in some cases.
- The defence is based on public policy and aims to protect the integrity of the legal system.
- The current test is set out in Patel v Mirza: purpose of the prohibition, other public policies, and proportionality.
- There must be a close connection between the claimant’s illegal conduct and the claim.
- The defence is most likely to succeed where the claim arises directly from serious criminal conduct.
- If the defence applies, the claim fails entirely, regardless of the defendant’s negligence.
Key Terms and Concepts
- ex turpi causa non oritur actio
- public policy
- Patel v Mirza test
- close connection
