Defences to Negligence in Tort Law: Volenti, Contributory Negligence and More

Imagine you are knocked down by a danfo bus on Ikorodu Road, Lagos. You have a broken leg, medical bills, and two weeks of lost income. You instruct a lawyer, who confirms that the bus driver was clearly negligent. You file your claim, confident in the outcome.

Then the defendant’s lawyer stands up and says: “Yes, our client was negligent. But the plaintiff was crossing at the wrong point on the road, wearing dark clothing at night, without looking left or right.”

Suddenly, your apparently straightforward case has a complication. This is what defences to negligence do. They either completely defeat a plaintiff’s claim, or reduce the damages awarded, even where negligence is clearly established.

This article examines the five principal defences available to a defendant in a Nigerian negligence action. Before reading this, you should be familiar with the four elements a plaintiff must first prove, which are discussed in our companion article on Negligence in Torts.

The main defences are:

1. Volenti Non Fit Injuria (Consent)
2. Contributory Negligence
3. Act of God
4. Act of a Stranger
5. Novus Actus Interveniens

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1. Volenti Non Fit Injuria

Volenti non fit injuria is a Latin maxim meaning “to a willing person, no injury is done.” It is a complete defence. If successfully established, the defendant escapes all liability and the plaintiff recovers nothing.

The underlying logic is simple: if you knowingly and voluntarily accepted a risk, you cannot later turn around and blame someone else when that risk materialises.

The Nigerian Position

Nigerian courts have addressed this defence directly. In Dare v Fagbamila (2009) 14 NWLR (Pt. 1160) 177, the Court of Appeal stated:

“The principle of volenti non fit injuria has been the subject of a lot of misconceptions. This is a common defence in actions of negligence. It emphasizes the necessity for knowledge and consent. The question primarily is whether the plaintiff agreed to the breach of the duty of care by the defendant towards him or, at least, to waive his right of action arising out of such breach.”

This formulation makes two things clear: knowledge alone is not enough, and consent alone is not enough. Both must exist, and the consent must specifically extend to the defendant’s negligent conduct, not merely to the general risk of the activity.

Two Elements the Defendant Must Prove

Element 1: The plaintiff knew of the risk. This is the scienti requirement. The plaintiff must have had actual knowledge of the specific risk that caused the injury, not just a vague awareness that the activity was dangerous. Mere knowledge of a potential danger is not the same as consenting to it.

Element 2: The plaintiff voluntarily accepted the risk. This is the volens requirement. Knowing the risk and freely choosing to accept it. Critically, the consent must be freely given. Consent obtained by coercion, economic necessity, or fraud is not valid.

Consent Must Be Truly Voluntary

This is where the defence frequently fails in practice. Consider a factory worker in Aba who continues working on a machine he knows is faulty, because refusing to do so would cost him his job. He knows the risk. But has he truly consented to it freely? Nigerian and English courts are reluctant to say yes, because economic pressure undermines genuine voluntariness.

Similarly, a hospital patient who signs a standard consent form before surgery consents to the procedure, not to carelessness during it. Volenti does not protect a negligent surgeon simply because the patient signed a pre-operation consent form.

The Okada Passenger Problem

This question has very real practical implications in Nigeria. An okada (commercial motorcycle) passenger in Kano who climbs onto a motorcycle without a helmet, knowing that the rider is unlicensed and the motorcycle has bad brakes, arguably knows the risk. But does he truly consent to being injured by reckless riding? Nigerian courts would look closely at whether there was genuine choice or whether the passenger simply had no other affordable transport option.

Contrast this with a passenger who helps a visibly drunk motorcycle rider start his bike and then rides with him, knowing he is heavily intoxicated. In Morris v Murray (1991) 2 QB 6, an English court held that a plaintiff who willingly took a flight with a pilot he knew had consumed the equivalent of 17 whiskies had, through his conduct, voluntarily accepted the risk. The defence succeeded. A Nigerian court faced with similar facts would likely reach the same conclusion.

Knowledge Is Not Consent: Dann v Hamilton

The most important limitation of the defence is illustrated in Dann v Hamilton (1939) KB 509. The plaintiff voluntarily got into a car driven by a man she knew was drunk. An accident occurred and she was injured. The court held that mere knowledge that the driver was drunk, and choosing to travel with him anyway, was not sufficient to establish volenti. Mere awareness of risk is not the same as accepting or consenting to the specific risk of injury from negligent driving.

The defence would require something more: an express agreement to waive any claim, or conduct so unambiguous that it amounts to an implied waiver.

Sports and Recreational Activities

Where a plaintiff voluntarily participates in a contact sport, they impliedly consent to the ordinary risks of that sport. A footballer who slides for a fifty-fifty tackle in a Sunday league game in Enugu accepts the risk that he may be legitimately challenged for the ball. A boxer who enters the ring accepts the risk of being punched.

In Simms v Leigh Rugby Football Club (1969) 2 All ER 923, a rugby player thrown into a concrete wall during a tackle was held to have consented to the physical risks of rugby, as the wall’s position was within the League’s byelaws. However, this consent has limits.

In Condon v Basi (1985) 2 All ER 453, a reckless, illegal sliding tackle that fractured the plaintiff’s leg went beyond the ordinary risks of football. The court held that participants still owe each other a duty of care appropriate to the sport, and consent to ordinary physical contact does not extend to reckless or dangerous play.

2. Contributory Negligence

Unlike volenti, which is a complete defence, contributory negligence is a partial defence. It reduces the plaintiff’s damages in proportion to their share of fault, but it does not extinguish the claim entirely. The plaintiff gets less, not nothing.

Contributory negligence is defined as the plaintiff’s own fault which partly caused the injury suffered. The Supreme Court in Evans v Bakare (1973) 3 SC 77 explained it as meaning that the party charged is primarily liable, but that the party charging him has “contributed by his own negligence to what has eventually happened.”

The Old Rule and the Modern Rule

At common law, contributory negligence was once a complete defence. If the plaintiff contributed at all to his own injury, he recovered nothing. This produced harsh results. Today, the position in Nigeria (following the English Law Reform (Contributory Negligence) Act 1945, which has been received into Nigerian law) is that the court apportions damages according to the respective degrees of fault. A plaintiff who is forty percent responsible for his own injury recovers sixty percent of his damages from the defendant.

Real Nigerian Examples of Apportionment

The Abeokuta-Lagos Road Case

In Oyelowo v De Bank Transport Ltd (1973) 2 WSCA 35, the plaintiff’s tanker was travelling along the Abeokuta-Lagos road when the defendant’s trailer, which had been parked on the roadside without warning lights or markers, suddenly pulled out into the road. The plaintiff’s driver swerved to avoid a collision and the tanker somersaulted into a ditch.

The Western State Court of Appeal apportioned liability as follows: the defendant was sixty percent negligent for pulling out without warning, and the plaintiff’s driver was forty percent contributorily negligent for attempting to overtake the trailer rather than stopping safely behind it. The plaintiff’s damages were accordingly reduced by forty percent.

This is exactly how contributory negligence works in practice: not a complete defeat, but a proportionate reduction.

The Cyclist Who Did Not Look

In Olayinka v Lakin (1972) 4 CCHCJ 100, the dependants of a deceased cyclist brought an action under the Fatal Accidents Law. The defendant’s negligent driving caused the accident, but the evidence showed that the deceased cyclist had moved into the road without properly looking. The court held the deceased seventy percent contributorily responsible for the accident and the defendant only thirty percent liable. The dependants’ award was reduced by seventy percent.

Failure to Wear Safety Equipment

This is the most commonly encountered form of contributory negligence in Nigerian road accident cases, and it is worth understanding the principle precisely.

Not wearing a seat belt or a crash helmet does not cause the accident. It contributes to the severity of the injury. This is an important distinction. A pedestrian struck by a negligent driver on Ahmadu Bello Way in Abuja is not contributorily negligent simply for being on the road. But a passenger in a danfo who was not wearing a seat belt (assuming one was available and functional) may have her damages reduced if medical evidence shows the seat belt would have reduced the severity of her injuries.

In O’Connel v Jackson (1972) 1 QB 270, the plaintiff rode a moped without a crash helmet. The defendant negligently knocked him down. The court held that although the defendant caused the accident, the absence of a helmet was a contributory causative factor in the extent of the plaintiff’s head injuries, and his damages were reduced accordingly.

The same principle applies in Pasternack v Poulton (1973) TLR 13.2.73, where a passenger who failed to wear an available seat belt had her damages reduced after suffering facial injuries in a collision caused by the defendant’s negligent driving.

In Nigeria, this principle is highly relevant given that the Federal Road Safety Corps (FRSC) mandates the wearing of seat belts and crash helmets under the Federal Road Safety Commission (Establishment) Act. Failure to comply with these safety regulations in circumstances where the safety equipment would have reduced injury is strong evidence of contributory negligence.

Contributory Negligence and Motorcycles

Given the prevalence of motorcycles in Nigerian transportation, it is worth noting: an okada passenger who refuses a crash helmet offered by the rider, or one who is fully aware the rider has no licence and gets on anyway, may face a contributory negligence argument if they are injured. Awareness and acceptance of an identifiable, manageable risk is the key issue.

3. Act of God

An act of God is a complete defence. It operates where the damage was caused by natural forces or events that were entirely outside human control and that could not have been foreseen or prevented by any amount of care and diligence.

James LJ defined it in Nugent v Smith (1876) 1 CPD 428 as “any accident due to natural causes directly and exclusively without human intervention and that could not have been prevented by any amount of foresight and pains and care.”

What Qualifies as an Act of God in Nigeria?

This defence is most relevant in Nigeria in contexts involving:

Flash floods: Nigeria experiences sudden, severe flooding events, particularly in states like Anambra, Kogi, and Delta during the rainy season. Where a river bursts its banks due to an unprecedented rainfall event, sweeps away a vehicle parked by a river, and injures the occupants, the vehicle owner may have a defence of act of God against a claim. However, if the flooding was foreseeable (for example, if previous floods had occurred in that location, or if flood warnings had been issued), the defence may fail.

Severe windstorms: A sudden, violent windstorm of the kind that occasionally sweeps through northern Nigeria, toppling trees and structures, may constitute an act of God if the event was truly exceptional and unforeseeable.

Lightning strikes: A lightning strike that starts a fire on a defendant’s premises, which then spreads to a neighbour’s property, is a classic act of God scenario, provided the defendant had taken reasonable precautions and the strike was genuinely unforeseeable.

The Critical Limitation: Foreseeability

The defence fails the moment any element of human fault or foreseeability is introduced. A property developer in Lagos who builds on a flood plain without proper drainage, and whose development floods a neighbouring property during the rains, cannot plead act of God. The flooding was foreseeable, and the absence of adequate drainage systems reflects a failure of reasonable care.

In other words, the act of God defence only applies to events that are truly exceptional and entirely outside human control. Ordinary Nigerian weather events, including heavy rain in the wet season, do not qualify.

4. Act of a Stranger

Where the damage was caused not by the defendant’s own conduct but by the independent wrongful act of a third party over whom the defendant had no control, the defendant may escape liability.

In Rickards v Lothians (1913) AC 263, water overflowed from the defendant’s upper floor and damaged the plaintiff’s property on the floor below. The cause was a waste pipe that had been deliberately blocked by a malicious stranger. The court held that the defendant was not liable because he neither instigated the act nor could reasonably have foreseen and prevented it.

Application in Nigeria

Consider a fuel station in Ibadan where a third party, acting entirely on their own initiative, removes a safety cap from a storage tank overnight, causing a fuel leak that eventually damages a neighbouring property. If the station management had no knowledge that the cap had been removed, had taken all reasonable precautions to secure the premises, and could not have foreseen the act, the defence of act of a stranger may succeed.

However, the defence has a firm limitation: if the defendant ought reasonably to have anticipated and guarded against the acts of strangers, and failed to do so, the defence will fail. A defendant who knows that children regularly trespass on his property and interfere with dangerous equipment, but takes no steps to secure it, cannot rely on the act of a stranger when one of those children is injured.

5. Novus Actus Interveniens

Novus actus interveniens means “a new act intervening.” It is the doctrine that breaks the chain of causation between the defendant’s negligence and the plaintiff’s damage, where a new and independent act (whether by a third party or even by the plaintiff themselves) steps into the sequence of events and becomes the real cause of the harm.

Where novus actus is established, the defendant is either fully or partially relieved of liability, even though their original negligence set the events in motion.

The Core Question

The central question in every novus actus case is: was the intervening act foreseeable? If the defendant ought reasonably to have foreseen that a third party might act in this way, the chain of causation is not broken. If the intervening act was wholly unforeseeable, the chain is broken and the defendant is not liable for the ultimate harm.

Intervening Act of a Third Party

In Stansbie v Troman (1948) 2 KB 48, a decorator left a house unlocked while he went out, contrary to the owner’s instructions. A thief entered and stole jewellery. The court held that the decorator could not rely on the thief’s act as a novus actus. It was entirely foreseeable that leaving a house unlocked would create a risk of burglary. The decorator remained liable.

Apply this to a Nigerian scenario: a security company hired to guard a warehouse in Apapa leaves its post without authorisation. Thieves break in and steal goods. The security company cannot say the thieves’ act breaks the chain of causation, because the risk of theft is precisely the risk the company was employed to prevent. A thief entering an unguarded premises is entirely foreseeable.

Contrast this with a case where the defendant’s negligence creates a situation, and a third party then commits a wholly independent, highly unusual criminal act that no reasonable person would have anticipated. In that case, the intervening act may be sufficiently unforeseeable to break the chain.

Intervening Act of the Plaintiff: A Uniquely Nigerian Case

The most instructive Nigerian illustration of this doctrine is the case of Ekwo v Enechukwu (1954) 14 WACA 512.

The plaintiff was in the defendant’s lorry when it had an accident, and the plaintiff was injured in the hand due to the negligent fixing of a seat in the lorry. Immediately after the accident, the defendant’s servant offered to take the plaintiff to a hospital for necessary medical attention. The plaintiff refused and instead went to a native doctor. Seven days later the plaintiff went to a hospital, by which time the hand had become infected and gangrenous and was amputated. The doctor in evidence said that if the plaintiff had gone to hospital immediately after the accident, the amputation might have been avoided.

The West African Court of Appeal held that the defendant was liable. The plaintiff had not acted unreasonably in consulting a native doctor instead of going immediately to a hospital. The court noted that this occurred in Nigeria, where a considerable proportion of the population holds a strong belief in native doctors, and those with the time to consider the matter and not sharing that belief are nonetheless able to see why a person might take that course.

This is a remarkable judgment in the Nigerian context. It confirms that the plaintiff’s conduct must be assessed against the cultural and social realities of Nigeria, not merely against what an English court might regard as reasonable conduct.

Compare this to Mange v Drurie (1970) NNLR 62, where the plaintiff was knocked down by the defendant’s lorry and taken to hospital. After his treatment was substantially complete, the plaintiff discharged himself against medical advice and did not return to hospital for two days, during which his leg became infected and was amputated. The court held that the defendant was not liable for the loss of the leg, because the plaintiff’s own unreasonable decision to leave the hospital against medical advice was the intervening cause of the amputation.

The difference between these two cases is instructive: in Ekwo v Enechukwu, going to a native doctor was reasonable in the circumstances. In Mange v Drurie, discharging yourself against explicit medical advice and then ignoring your injury was unreasonable. Unreasonable conduct by the plaintiff is a novus actus; reasonable conduct, even if unorthodox, is not.

Practical Summary: Which Defence Should a Defendant Raise?

Frequently Asked Questions

Can the defendant use more than one defence at the same time? Yes. A defendant may plead volenti and contributory negligence in the alternative, or rely on novus actus alongside contributory negligence. Courts will consider each on its merits.

Does contributory negligence completely defeat a negligence claim in Nigeria? No. Under modern Nigerian law, contributory negligence only reduces the plaintiff’s damages proportionate to their degree of fault. The plaintiff still recovers the remainder from the defendant.

If someone boards an okada in Nigeria knowing it is dangerous, can the okada operator escape liability by pleading volenti? Not automatically. The plaintiff must have knowingly accepted the specific risk of injury from the operator’s negligence, not merely the general risk of riding on a motorcycle. Most Nigerian courts would not readily apply volenti in a standard okada accident unless the facts showed something beyond ordinary risk, such as the passenger encouraging reckless riding.

Can flooding in Nigeria constitute an act of God? Only if the flooding was truly exceptional and unforeseeable. Regular seasonal flooding that is known to occur in a particular area will not qualify. The defence requires a natural event that no amount of foresight could have anticipated or prevented.

Conclusion

The defences to negligence are not technicalities invented to help wrongdoers escape responsibility. They reflect genuine principles of fairness: a person who contributed to their own injury should bear part of the cost, a person who consented to a risk cannot later deny it, and a defendant should not be held responsible for harm caused by events entirely beyond their control.

For Nigerian law students and practitioners, the most practically significant of these defences are contributory negligence and novus actus interveniens, given the frequency of road accident litigation and the complex causation questions that arise in medical treatment and multiple-party accident cases.

For the complete picture of negligence, read our companion article on Negligence in Torts. For related reading on claims where someone dies as a result of negligence, see our article on Death as a Cause of Action.

References:

• Eni Eja Alobo, Law of Tort (Princeton Publishing Company, 2013)
• Kodilinye and Aluko, The Nigerian Law of Torts (Spectrum Books, Lagos, 1995)
• Ese Malemi, Law of Tort (Princeton Publishing Company, 2013)
• Dare v Fagbamila (2009) 14 NWLR (Pt. 1160) 177 (Court of Appeal)
• Ekwo v Enechukwu (1954) 14 WACA 512