Core principles of tort - Defences to negligence

Learning Outcomes

This article examines the core defences to negligence under English law, including:

• Identifying and clearly defining consent (volenti non fit injuria), contributory negligence, and illegality (ex turpi causa) as the principal defences to negligence claims.
• Distinguishing between complete and partial defences and explaining how each operates in practice to defeat liability or reduce recoverable damages.
• Analysing the essential elements of consent, including full knowledge and voluntary acceptance of risk, and recognising situations where genuine volenti is unlikely, such as employees, rescuers, or passengers.
• Applying the Law Reform (Contributory Negligence) Act 1945 to apportion damages on a “just and equitable” basis, assessing the claimant’s share of responsibility for their injuries.
• Evaluating when the defence of illegality bars a claim by reason of the claimant’s serious criminal or unlawful conduct, using the modern policy-based proportionality approach.
• Explaining how these defences interact with other tort claims, including occupiers’ liability and product liability, and how statutory controls such as the Road Traffic Act 1988 restrict their operation.
• Advising on realistic SQE2-style scenarios, avoiding common analytical errors and justifying whether a defence should succeed or fail and how it will affect remedies and the reduction of damages.

SQE2 Syllabus

For SQE2, you are required to apply core defences to negligence in client scenarios, written advice, and oral explanations, with a focus on the following syllabus points:

• the constituent elements and legal requirements for each principal defence to negligence
• how consent, contributory negligence, and illegality operate and are limited by relevant statutory provisions
• practical application: recognising when consent or contributory negligence is likely to succeed or fail on facts, including for specific categories such as passengers, children, employees, and rescuers
• understanding when each defence provides partial or complete relief from liability, and how courts apportion damages
• statutory restrictions and public policy: for example, the operation of s.149 Road Traffic Act 1988 and the interaction with occupiers’ liability or product liability claims
• procedural aspects, including the effect on damages, liability, and any right to claim a contribution
• how the defences interact with claims involving illegality (ex turpi causa), criminal acts, or misconduct
• awareness of key pitfalls in application (e.g., mere knowledge of risk is not sufficient for consent, and illegality requires a direct link to the tortious act)
• accurately reflecting current UK case law and statutory law in your legal analysis as required by the SQE2 specification

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.

1. A driver negligently injures a passenger. The passenger knew the driver was uninsured and intoxicated and accepted a lift. Which defence(s) might be available?
2. What two elements must a defendant prove to establish the defence of consent (volenti) in negligence?
3. Does a finding of contributory negligence completely defeat a claim?
4. If a claimant is injured while jointly committing a burglary, can they recover damages in negligence?

Introduction

Negligence as a cause of action is subject to three principal defences: consent (volenti non fit injuria), contributory negligence, and illegality (ex turpi causa non oritur actio). These defences play a critical role in the apportionment or exclusion of liability and reflect both technical legal requirements and the practical realities of litigation. To advise effectively on potential tort disputes you must fully understand the requirements, limits, and implications of each defence, including their statutory regulation and practical application to different claimant and defendant relationships.

Key Term: consent (volenti non fit injuria)
The complete defence that a claimant freely and voluntarily agreed to accept the risk of injury arising from the defendant’s negligence.

Key Term: voluntary assumption of risk
The principle that a claimant, with full knowledge, willingly accepted the risk arising from the defendant’s conduct.

Key Term: contributory negligence
A partial defence that reduces the claimant’s damages where their own lack of reasonable care has contributed to the harm suffered.

Key Term: illegality (ex turpi causa non oritur actio)
A complete defence barring a civil claim when the claimant’s action arises directly from, and is inseparably connected to, illegal conduct or serious wrongdoing.

Defences to Negligence

The operation, development, and current statutory controls of key negligence defences are set out in detail below.

Consent (Volenti Non Fit Injuria)

Consent is available as a complete defence in negligence if the defendant can establish that the claimant:

• had full knowledge of the nature and extent of the relevant risk; and
• voluntarily and freely agreed, expressly or impliedly, to bear that risk.

It is not sufficient that the claimant was merely aware of the risk. There must be evidence of actual, genuine acceptance of the risk, and such acceptance must be both free from compulsion and informed by knowledge of the precise danger.

Courts scrutinise claims of consent rigorously—particularly where there is an imbalance of power, compulsion, employment, or no viable alternative but to accept the risk. In employment contexts and most consumer or service relationships, it is rare for true volenti to be established absent clear and uncoerced agreement.

Consent, if proven, completely bars the claim in negligence—no damages are available, irrespective of the injury. However, statutory restrictions mean that it cannot always be relied upon.

Worked Example 1.1

A passenger agrees to a lift from a driver they know is drunk. Later, due to the driver’s negligence, a crash occurs and the passenger is injured. Can the driver argue consent?

Answer:
The driver may try to argue consent because the passenger knew of the state of intoxication. However, courts are unlikely to find that the passenger truly accepted the risk of negligent driving unless the danger was glaring and the acceptance entirely voluntary. If the accident involves a motor vehicle, statute prevents the consent defence for passengers.

Volenti in Law and Practice

True consent requires more than just knowledge of risk. The claimant must also have a real opportunity to choose whether to accept the risk or not. Mere acquiescence or passive acceptance is not enough. The defence will fail unless there is clear evidence of positive, voluntary assumption of risk.

For example, in employment circumstances, the defence frequently fails as employees are not usually in a position to make a free, informed choice due to economic necessity or contractual duties. Courts are also slow to find that rescuers, who intervene in emergencies, acted voluntarily rather than out of moral, social, or professional compulsion.

Volenti may be more easily established in context of certain sports or recreational activities where participants consent to risks ordinarily associated with the activity (but not to negligence beyond the ordinary risks or to serious breaches of rules).

Statutory Restrictions

Parliament has intervened to remove or modify the defence of consent in some areas of high policy concern. In particular, the Road Traffic Act 1988 s.149 renders agreements seeking to exclude or restrict liability for death or personal injury to a passenger in a motor vehicle void. As a result, a passenger injured as a result of negligent driving cannot be said to have consented so as to bar a claim, even where they knowingly accepted a lift from a drunk driver. The rationale is clear public policy: to prevent drivers and insurers from escaping liability and to protect vulnerable road users.

Some other statutes also restrict reliance on consent in specific contexts (e.g., product liability and certain occupiers’ liability cases), placing additional limits on the scope of the defence.

Worked Example 1.2

A professional climber takes part in a dangerous climbing competition, having read and signed a comprehensive risk acknowledgement form which spells out the nature of the hazards. During the event, she is injured as a result of a risk ordinarily associated with climbing (e.g., a rockfall) but not due to any negligence. Does consent bar her claim?

Answer:
Yes—where a participant in a high-risk activity gives informed, voluntary consent specifically accepting the relevant risks, the defence of volenti applies and the claim is barred so long as the injury arises solely from those risks and not from an additional negligent act which exceeds what was reasonably expected.

Inadequacy of Consent: Key Pitfalls and Practical Points

• Knowledge of risk ≠ Acceptance: The claimant may be aware of the risk but still not consent to it.
• No genuine choice, no volenti: Circumstances involving necessity, compulsion, inequality of bargaining power, or indirect duress usually defeat the defence.
• Consent is negated by fraud, mistake, or misrepresentation as to the nature or extent of the risk.
• Third parties: Consent by a third party is only effective if the actual claimant had knowledge and free acceptance.
• In clinical negligence, informed consent must be genuine, encompassing both risks of the treatment and alternatives.

Exam Warning

The defence of consent is strict: mere knowledge of the risk is not enough—willing acceptance is required. Watch for SQE2 questions relying only on knowledge.

Worked Example 1.3

At a football match, X is injured by a legitimate tackle within the rules. Y sues for negligence. Will consent succeed as a defence?

Answer:
Yes—by participating in the sporting event, X consents to risks ordinarily associated with the sport and reasonable play. But consent will not cover injuries caused by conduct that is outside the scope of the rules or grossly reckless.

Consent and Specific Groups

• Employees: The defence rarely succeeds as true freedom of choice is lacking.
• Rescuers: Courts are unlikely to find that a rescuer has voluntarily consented to risk—they act out of moral compulsion, not free choice.
• Statutory barriers: For certain relationships—passengers in motor vehicles—statute expressly removes the ability to rely on consent.

Contributory Negligence

Contributory negligence is a partial defence that reduces the sum recoverable by a claimant in negligence in proportion to their share of responsibility for the harm.

Section 1(1) of the Law Reform (Contributory Negligence) Act 1945 provides:

“Where any person suffers damage as the result partly of his own fault and partly of the fault of any other person... a claim in respect of that damage shall not be defeated by reason of the fault of the person suffering the damage, but the damages recoverable... shall be reduced to such extent as the court thinks just and equitable having regard to the claimant’s share in the responsibility for the damage.”

Crucially, the defence does not defeat liability completely. Instead, it only reduces damages—often considerably, but always proportionate to the claimant’s own failings.

Scope and Operation

To establish a finding of contributory negligence, the defendant must prove:

• The claimant failed to take reasonable care for their own safety, and
• That failure contributed, in whole or in part, to the harm suffered (not just to the accident, but to the injury or damage actually incurred).

This assessment is factual and focuses on the injury sustained—not necessarily the cause of the accident. The claimant’s behaviour is measured by reference to the standard of a reasonable person in the same circumstances. Where the claimant is a child, allowance is made for age and understanding.

Damages are reduced by the court in such proportion as is just and equitable, taking into account both the claimant’s culpability and the contribution that their negligence made to the loss.

Worked Example 1.4

A car accident is caused entirely by D. C, a passenger, is not wearing a seatbelt and suffers injuries that would have been less severe with a seatbelt. Will C’s damages be reduced?

Answer:
Yes. Not wearing a seatbelt was a failure to take reasonable care for one’s own safety. Damages are reduced according to the injury that would have been prevented (e.g., 25% if all injury would have been avoided; see Froom v Butcher guidelines).

Contributory negligence is assessed on a case-by-case basis. Typical factors considered by the court include the seriousness and blameworthiness of the claimant’s conduct, causation, and the proportionality of the responsibility shared.

Worked Example 1.5

A cyclist is hit by a car after failing to stop at a red light. The driver was speeding but the cyclist’s conduct was also a material cause of the accident. Will the claimant recover?

Answer:
The cyclist’s damages will be reduced in proportion to their own contribution to injury. If both are partly responsible, each share of blame is assessed and the claimant will not be denied all damages.

Special Considerations

• Minors: For children, the court determines what is reasonably expected taking age into account. Young children are seldom found contributorily negligent.
• Recklessness and intoxication: If a claimant accepts a ride with a drunk driver, the court may find contributory negligence even if consent (volenti) is barred by statute.
• Employees: Where claimants fail to follow safety instructions, their damages may be reduced but are seldom eliminated completely.

Application in Product and Occupiers' Liability

• Product liability (common law): If a claimant ignores clear dangers or warnings and suffers injury, damages may be reduced.
• Occupiers’ liability: If a visitor disregards reasonable precautions, courts may find contributory negligence, reducing damages accordingly.

Revising the Test for Contributory Negligence

• The reduction in damages depends on the factual matrix—what proportion was due to the claimant’s own actions? Courts will not reduce damages by 100% except in rare or extreme circumstances.

Revision Tip

Always identify which injuries were contributed to by the claimant’s negligence. Contributory negligence usually does not defeat the claim but reduces any damages awarded.

Illegality (Ex Turpi Causa Non Oritur Actio)

Illegality provides a complete defence to a claim in negligence where the claimant’s own unlawful or criminal conduct is sufficiently connected to the harm suffered such that it would be contrary to public policy for the law to assist the claimant.

To succeed, the defendant must establish:

• The claimant’s cause of action arises directly from, or is inseparably connected to, a serious illegality (often criminal activity), and
• Permitting the claim would affront public policy or undermine the administration of justice.

Courts consider three main rationales for the doctrine of illegality:

• Public conscience: The law should not assist a claimant in profiting from their own wrongdoing.
• Deterrence: Courts discourage parties from entering into or pursuing illegal acts.
• Integrity of the legal system: Upholding the rule of law by denying judicial assistance where a claim offends fundamental public interest.

There must be a sufficiently close connection between the illegality and the harm. The mere presence of unlawful behaviour is not enough—the defendant must show the injury was caused during the commission or as a consequence of the illegal act.

Worked Example 1.6

C and D are jointly carrying out a burglary. C is injured through D’s negligent driving during their escape. Can C sue D for damages?

Answer:
The claim will fail. Injury was sustained in the course of joint criminal enterprise. Applying the defence of illegality, a civil claim is barred.

Modern Approach and Judicial Discretion

Following recent case law, courts now approach illegality as a matter of policy, weighing whether denying the claim is a proportionate and justified response in all the circumstances. Factors include the seriousness of the illegality, the centrality of the illegality to the claim, whether denial of relief would be a fair response, and potential paradoxes or injustice to third parties. However, where the claim arises directly out of a criminal act, especially serious crimes involving harm to others, the defence will almost always succeed.

Not all illegal acts will bar a claim—for instance, minor regulatory breaches or conduct that is only tangentially connected will usually not suffice. The illegality must be grave and central to the circumstances of the injury.

Exam Warning​

Illegality is a complete defence only when the connection between the harm and offence is close and denial of relief is proportionate—assess the factual link carefully in exam scenarios.

Interaction of Defences and Further Points

• The distinction between consent and contributory negligence is subtle but important: consent bars liability completely if established; contributory negligence only reduces damages. Both may be pleaded but cannot operate simultaneously for the same conduct.
• Statutory bars: For example, in personal injury actions arising from road traffic accidents, s.149 Road Traffic Act 1988 can prevent reliance on consent but not on contributory negligence.
• The Law Reform (Contributory Negligence) Act 1945 provides for judicial discretion and flexibility in apportionment—there is no fixed reduction, and reductions should be “just and equitable” based on all circumstances.
• Sometimes consent and illegality overlap—injury suffered jointly in the commission of a crime will generally bar recovery on both bases.

Worked Example 1.7

A passenger, aware the driver is intoxicated and uninsured, encourages the driver to evade pursuing police and is injured during the resulting crash. Can the passenger claim?

Answer:
The passenger’s damages may be barred by illegality as they participated in a joint criminal enterprise. Even where consent is not effective (if s.149 applies), the close connection between the unlawful conduct and injury will normally preclude recovery.

Consent in the Context of Occupiers’ or Product Liability

• In occupiers’ liability claims, consent remains a defence if the visitor had full knowledge and acceptance of risk, provided it was not excluded by statute.
• For product liability, consent is rare—most consumer injuries do not arise from informed, voluntary risk-taking.

Consent and Exclusion of Liability

Exclusion of liability clauses in contract or notices may attempt to rely on consent-type arguments, but such provisions are strictly regulated or void for personal injury or death (see Unfair Contract Terms Act 1977 and Consumer Rights Act 2015).

Table: Summary — Application of Defences

Key Point Checklist

This article has covered the following key knowledge points:

• Consent (volenti non fit injuria) requires full knowledge of the risk and a voluntary, genuine acceptance. Mere knowledge is insufficient—free, informed choice is essential.
• Consent is a complete defence and bars a negligence claim entirely. Statutory provisions such as s.149 RTA 1988 may prohibit reliance on consent in specified contexts.
• Contributory negligence is a partial defence that leads to a reduction in damages, not an extinguishing of liability. Damages are apportioned according to the claimant’s responsibility.
• The test for contributory negligence focuses on whether the claimant failed to take reasonable care for their own safety and contributed to the harm suffered, not simply to the accident.
• The court may apportion contributory negligence flexibly, guided by what is just and equitable in the circumstances, reflecting modern principles of comparative fault.
• Illegality (ex turpi causa) is a complete defence where the claim is based on or arises directly from the claimant’s serious criminal or unlawful act, or where it would affront public policy to allow the claim.
• Illegality will not bar a claim for every unlawful act—the link must be direct and significant, and the courts apply a policy-based, proportionate analysis.
• In exam and practice scenarios, you must analyse the connection between the claimant's conduct and the harm, consider all statutory restrictions, and differentiate carefully between complete and partial defences.
• Rescuers and employees are rarely found to have genuinely consented to risk, and may not be held contributorily negligent in emergency contexts unless their actions were wholly unreasonable.
• Exclusion of liability clauses may not circumvent the defences in the case of personal injury or death; regulatory statutes may impose limitations.

Key Terms and Concepts

• consent (volenti non fit injuria)
• voluntary assumption of risk
• contributory negligence
• illegality (ex turpi causa non oritur actio)