Introduction
Novus actus interveniens, a Latin term meaning "a new intervening act," represents a crucial concept within the legal framework of causation. It addresses situations where an event occurs after the initial wrongful action, thereby breaking the direct causal link between the initial action and the resulting harm. The technical principle underlying this doctrine is that a defendant should not be held liable for consequences that are not a direct result of their actions but are instead attributable to an independent intervening cause. The key requirements for a successful application of novus actus interveniens involve an examination of whether the intervening act was both independent of the initial wrong and sufficiently significant to sever the causal chain. This doctrine applies in both criminal and civil law. It considers the voluntary and informed nature of the intervening act, its foreseeability, and its impact on the chain of events.
The Concept of Intervening Acts
An intervening act can manifest in several forms, including actions by the victim, third parties, or even natural events. For an act to qualify as a novus actus interveniens, it must disrupt the natural and probable sequence of events that flowed from the defendant’s original wrongdoing. The act must be an independent and voluntary action that is not a reasonably foreseeable consequence of the defendant’s initial conduct. The primary focus is to determine whether the intervening event is significant enough to shift legal responsibility away from the original wrongdoer. This is not simply a question of chronological order, but of whether the intervening event carries enough causal weight to supersede the original action.
For example, in the case of R v Kennedy [2007] UKHL 38, the House of Lords found that the victim’s voluntary act of self-injecting heroin, provided by the defendant, was a novus actus interveniens, breaking the chain of causation that would have otherwise led to the defendant being held liable for manslaughter. In contrast, in R v Pagett (1983) 76 Cr App R 279, the Court of Appeal held that the police officer's return fire in self-defense was not a novus actus interveniens, because it was a reasonable act directly resulting from the defendant’s initial aggression. These cases show how the judiciary assesses the voluntariness and foreseeability of intervening actions.
Voluntariness and Informed Choice
The concept of voluntariness is central to novus actus interveniens. If the intervening act is the result of a free and informed choice by the victim or a third party, this strongly indicates a break in the chain of causation. The law often assumes that adults of sound mind possess free will and are capable of making autonomous decisions that dictate their actions. The case R v Kennedy supports this principle, illustrating that the victim's fully informed decision to self-inject the heroin was a voluntary choice that severed the link of causation between Kennedy’s provision of the drug and the victim's subsequent death. Lord Bingham stated that criminal law generally recognizes that people have free will, and “informed adults of sound mind are treated as autonomous beings able to make their own decisions how they will act.”
However, it is important to note that not all acts of victims or third parties are considered fully voluntary. If the intervening act is a reaction to the initial wrong, particularly if it occurs due to duress, deception, or necessity, it might not qualify as a novus actus interveniens. In R v Wallace [2018] EWCA Crim 690, the Court of Appeal held that the victim's decision to undergo euthanasia, following severe disfigurement from an acid attack by the defendant, was not a novus actus interveniens, because it was not an act of "free and unfettered volition." The victim was under considerable pressure due to the severe injuries sustained. This decision indicates that the court considers the context and level of pressure influencing the intervening decision.
Reasonableness and Foreseeability
An intervening act that is a reasonable response to the initial wrong is unlikely to break the chain of causation. This is particularly true for acts of self-defense or the execution of legal duties. In R v Pagett, the police officer's actions in returning fire was viewed as a reasonable and foreseeable response to the defendant's initial unlawful act of shooting at him. Robert Goff LJ stated that “a reasonable act performed for the purpose of self-preservation, being of course itself an act caused by the accused’s own act, does not operate as a novus actus interveniens." Acts performed out of self-preservation or in the execution of a legal duty are considered a direct consequence of the original wrongdoing, thus upholding the chain of causation.
Conversely, an unreasonable action by the victim can break the chain of causation. In McKew v Holland and Hannen [1969] 3 All ER 1621, the claimant’s decision to descend steep steps unaided, despite a known leg injury due to the defendant’s negligence, was deemed an unreasonable action that broke the chain of causation. Lord Reid stated, "if the injured man acts unreasonably, he cannot hold the defender liable for injury caused by his own unreasonable conduct." The court considered that the victim’s decision was not merely a consequence of the initial injury but an independent act that led to further harm. Similarly, in Spencer v Wincanton Holdings [2009] EWCA Civ 1404, the court held that the victim’s act did not break the chain of causation because it was not sufficiently unreasonable.
Natural Events and "Acts of God"
Natural events can also constitute an intervening act, though typically, the law makes a distinction between natural events that are a typical part of life and those that are unforeseen or extraordinary. In the case of Carslogie Steamship Co Ltd v Royal Norwegian Government [1952] AC 292, the House of Lords determined that severe storm damage to a ship was a novus actus interveniens that broke the chain of causation stemming from a previous collision due to negligence. The storm damage, an unexpected and severe event, was deemed independent of the original collision. The defendant’s liability was limited to the damage resulting from the initial incident and not for additional damages caused by subsequent natural occurrences.
However, it is crucial to determine the foreseeability of the natural event. In Southern Water Authority v Pegrum [1989] Crim LR 442, heavy rain was not considered an Act of God, because it was a foreseeable event. The court held the pig farmers liable for pollution caused by a blocked drain and overflowing lagoon, stating the events were not so overpowering as to constitute an act outside their control. Therefore, a natural event must be extraordinary and unforeseeable to act as an effective novus actus interveniens.
Medical Interventions and Omissions
The actions or omissions by medical professionals may also be analyzed within the context of novus actus interveniens. Generally, negligent medical treatment will not break the chain of causation if the victim was initially harmed by the defendant’s actions. This is particularly so if the medical treatment is a reasonably foreseeable consequence of the defendant’s initial wrong. However, it can break the chain of causation if it was so palpably bad as to be considered an independent act. The principles behind this are similar to those applied in cases of third-party intervention, with an emphasis on foreseeability and reasonableness.
Furthermore, omissions of a victim to take certain steps, like accepting medical treatment, do not automatically break the chain of causation. In R v Blaue [1975] 1 WLR 1411, the court held that the victim’s decision to refuse a blood transfusion due to religious beliefs did not constitute a novus actus interveniens. The defendant was liable for manslaughter, because the initial stab wound was still considered the operating cause of death. The “egg-shell skull” rule was applied, stating the defendant must take their victim as they find them, including religious beliefs.
Novus Actus Interveniens in Negligence
In negligence, the principle of novus actus interveniens functions similarly to how it does in criminal law. An intervening act must be sufficiently significant to break the chain of causation between the defendant's negligence and the claimant's harm. The case of McKew v Holland and Hannen provides an example where the claimant’s unreasonable actions were considered a novus actus interveniens in the tort of negligence. The principle was re-affirmed in Spencer v Wincanton Holdings, with the court stating that the level of unreasonableness to break the chain of causation must be very high.
The case Knightley v Johns [1982] 1 WLR 349 offers another example. The court found that a negligent order by a police officer was a novus actus interveniens that broke the chain of causation between the initial negligent driving and the second police officer’s injuries. The test for causation in these cases is if the damage is reasonably foreseeable and a “natural and probable” cause of the defendant’s action. Thus, an intervention that is unforeseen or sufficiently unreasonable will negate liability in negligence.
Conclusion
Novus actus interveniens plays a vital role in determining legal responsibility by assessing the causal links between wrongful acts and subsequent harm. The concept evaluates intervening acts based on their independence, voluntariness, and foreseeability within the sequence of events. Cases such as R v Kennedy, R v Pagett, and R v Wallace in criminal law and McKew v Holland and Hannen, Knightley v Johns, and Carslogie Steamship Co Ltd v Royal Norwegian Government in civil law, illustrate the application of these criteria. The doctrine ensures that liability is appropriately assigned to those who directly cause harm, while protecting defendants from excessive liability for events indirectly connected to their actions. The analysis of novus actus interveniens requires a detailed examination of facts and legal precedent, ensuring that the law appropriately accounts for causal complexities when allocating responsibility.
