Illegality as a Defence in Personal Injury Claims
This article is one of a series of articles about defending personal injury claims. It focuses on the illegality defence (ex turpi causa) – a powerful but often overlooked argument that can completely defeat a claim.
In a recent case handled by our team, the claimant’s solicitor had never encountered this defence before and subsequently dropping the claim he was advancing on behalf of his client.
What is the illegality defence?
The illegality defence in personal injury claims prevents a claimant from recovering damages where their injury arises from their own criminal conduct.
Often referred to as “ex turpi causa”, the principle is grounded in the wider public policy notion that it would bring the whole legal system into disrepute if people were allowed to benefit from their own criminal conduct.
This defence can be particularly relevant in claims involving dangerous driving, criminal behaviour and joint illegal enterprises.
How the courts apply the illegality defence
The leading case on illegality is Patel v Mirza 2016. The Supreme Court confirmed that courts should adopt a flexible, public-policy based approach when considering the application of the defence.
In doing so, the court emphasised the need to have regard to the purpose of the law that has been breached, any competing public policy considerations, and whether denial of the claim would be a proportionate response. This approach replaced the previous rigid reliance test and means that outcomes may vary depending on the facts of each case.
Illegality in practice: Pitts v Hunt 1991
In the case of Pitts v Hunt 1991 the claim of a pillion passenger who encouraged a motorcyclist to ride recklessly, and who he knew to be intoxicated, was dismissed. When the claimant sued for injuries sustained in a collision between the motorcycle and a car, the court found that there was an ex turpi causa defence, as the claimant and first defendant were engaged in a joint illegal enterprise.
It was against public policy to allow the claimant to succeed. The nature of the joint enterprise was such that it precluded the court from finding that the defendant owed any duty of care to the claimant.
It is apparent that each case will turn on its own specific facts but that there are some general principles to be gleaned from the case law. The courts will look at the illegality involved, consider whether there are any competing public policy considerations engaged if a claim is turned down and the court will also look at matters proportionately and consider whether a claimant’s illegal act is closely connected to their claim or whether it is unrelated.
Kelvin Farmaner is a Partner and Head of the Insurance and Regulatory team at Trethowans. Contact Kelvin by email at [email protected] or telephone 023 8082 0527.
Our defendant insurance expertise is independently recognised by leading legal directories. Kelvin Farmaner is ranked UK‑wide by Chambers for Personal Injury: Mainly Defendant, while Trethowans is ranked in the Legal 500 for Personal Injury: Defendant (South East – Insurance), with both Kelvin Farmaner and Bethany Blamire named as Leading Partners, highlighting the strength and track record of our insurance disputes team.
This article was featured in the Expert Witness Journal (Issue 67, June/July 2026).
____________________________________________________________________________________________________
Disclaimer
This information is intended for general informational purposes only and does not constitute legal advice. We recommend seeking professional advice before taking any action on the information provided. If you would like to discuss your specific circumstances, please feel free to contact us on 0800 2800 421.
