What Is the Role of Causation in Public Liability Law?

In public liability law, establishing causation is essential to proving that a defendant's careless or negligent conduct not only breached a duty of care but also directly led to the claimant's injury or loss. Causation connects the defendant's actions or omissions to the harm suffered, and without it a claim cannot succeed-even if the duty of care and breach are clear. This article explains how causation operates within public liability claims in England and Wales, including the legal tests, key principles from case law, obstacles such as intervening events, and common questions that arise in practice.

What Is Causation?

In the context of a negligence or public liability claim, causation refers to proving that the defendant's breach of duty was both the factual and legal cause of the claimant's injury or damage. It underpins the legal responsibility to compensate: it is not enough to show that someone was negligent in abstract; the negligence must have caused actual harm to the claimant.

Causation serves as a bridge between the defendant's breach of duty and the loss suffered. If the chain of causation is not established or is broken by an independent event, a claim may fail on this element alone even when liability for breach is otherwise clear.

Two Parts of Causation: Factual and Legal

Factual Causation

Factual causation deals with whether the harm would have occurred “but for” the defendant's breach. This is often termed the “but for” test. Under this standard, a claimant must show, on the balance of probabilities, that:

• If the defendant had not been negligent, the claimant would not have suffered the loss or injury.
• The defendant's actions or omissions made a real and effective contribution to the harm.

For example, in a slip‑and‑fall claim, if poor maintenance of a floor is alleged, the claimant must show that the fall (and resulting injury) would not have happened without that negligent maintenance.

Legal Causation

Once factual causation is established, courts consider legal causation, also known as proximate causation or the scope of liability. Legal causation determines how far liability should extend and whether:

• The harm suffered was a reasonably foreseeable consequence of the defendant's breach.
• The link between the breach and the harm is sufficiently close and unbroken by intervening acts.

This component prevents liability being imposed for harm that, although factually linked, is too remote or unforeseeable to be fairly attributed to the defendant.

Case Law on Causation and Its Role

The “But For” Foundation

The “but for” test underpins factual causation and is a foundational element in negligence claims. Courts have emphasised that without such causation, no liability arises, regardless of how negligent the conduct was.

Material Contribution and Complex Causation

In some circumstances where multiple factors contribute to harm, courts may consider whether the defendant's conduct materially increased the risk of injury. Although the standard “but for” test remains primary, case law such as McGhee v National Coal Board recognised situations where a defendant's breach significantly raised the likelihood of harm.

However, not every case of increased risk results in liability. In Wilsher v Essex Area Health Authority, the House of Lords clarified that where multiple possible causes exist, the claimant must still show causation on the balance of probabilities; an increased risk alone did not suffice in that instance.

Foreseeability and Remoteness

Causation is also shaped by considerations of foreseeability and remoteness. The courts determine whether the type of harm suffered was a foreseeable outcome of the defendant's negligent act. In negligence generally, the Wagon Mound (No. 1) principle illustrates that liability is limited to harm that a reasonable person could foresee.

Case law such as Smith v Leech Brain & Co Ltd further illustrates how courts treat consequences that flow from an initial injury, including where the extent of harm is greater than anticipated due to claimant characteristics; under the eggshell skull rule, defendants remain liable for the full extent of harm as long as the initial harm was caused by negligence.

Intervening Events and Breaks in the Chain of Causation

A key aspect of legal causation is determining whether an intervening event (novus actus interveniens) breaks the chain linking breach to harm. Court decisions distinguish between foreseeable subsequent acts and those so independent or unforeseeable that they sever legal responsibility.

Examples of possible intervening factors include actions by third parties, natural events, or even claimant conduct that could overshadow the original negligent act. If such events break the causal chain, the defendant may not be held liable for subsequent harm.

Practical Application in Public Liability Claims

In a public liability claim, causation is assessed alongside the other elements of negligence:

• Duty of Care: Did the defendant owe a duty to the claimant?
• Breach: Did the defendant fail to uphold that duty?
• Causation: Did that breach cause the claimant's injury?
• Damage: Did the claimant suffer actual injury or loss?

Even if duty and breach are established, failure to prove causation will prevent recovery. For example, if a claimant cannot show that a fall was caused by the defendant's negligence rather than some unrelated factor, causation is not established and the claim fails.

Time Limits and Burden of Proof

Proof of causation forms part of the claimant's overall burden in a negligence claim, which must be met on the balance of probabilities - meaning the court must be persuaded that it is more likely than not that the defendant's breach caused the harm.

Standard time limits under the Limitation Act 1980 apply to public liability claims, with most claims needing to be issued within three years of the date of injury or date of knowledge. Establishing causation promptly and with robust evidence supports meeting procedural deadlines and strengthening the claimant's case.

Common Questions About Causation

Is causation the same as breach?
No. Breach refers to failure to meet a duty of care; causation links that breach to the claimant's actual harm. A breach without causation does not give rise to liability.

Can multiple causes affect liability?
Yes. Where several factors contribute to harm, courts assess whether the defendant's breach materially contributed to the injury on the balance of probabilities.

Can intervening events remove liability?
If an independent event breaks the causal chain, a court may conclude that the defendant's actions no longer legally caused the harm, limiting or removing liability.

Key Takeaways

Causation plays a central role in public liability law by connecting the defendant's breach of duty to the claimant's injury or loss. It requires proof of both factual causation - typically via the “but for” test - and legal causation, which considers foreseeability and whether the causal chain has been broken. Landmark case law illustrates how courts balance these elements to ensure liability is fairly attributed. Without establishing causation, a public liability claim cannot succeed, even if duty and breach are clear.

James William Steven Parker

James is the founder of UKLegalGuides.com and a former agent at the Ministry of Justice (UK). With a background in processing legal claims, he launched this platform to make the laws of England and Wales accessible to everyone.