Novus actus interveniens
Latin: A new act intervening.
Also called: Intervening act, Breaking the chain of causation
A new, independent act or event that intervenes between the defendant's conduct and the harm and breaks the chain of causation, so that the defendant is not liable for the harm that follows.
Explained
Novus actus interveniens refers to a new act that intervenes between the original wrong and the eventual damage. Liability in tort and in criminal law depends on causation: the defendant's act must be a cause of the harm in law, not merely in fact. If a new and independent cause intervenes and becomes the real cause of the harm, the chain of causation is said to be broken and the original wrongdoer is not answerable for the consequences that follow.
Not every intervening event breaks the chain. The intervening act may be that of a third party, of the claimant himself, or a natural event. It will usually break the chain only if it is free, deliberate and informed, or so unreasonable or unforeseeable that it overwhelms the original wrong. An act done instinctively, under the pressure of the danger the defendant created, does not; in the well known squib case, Scott v. Shepherd (1773), persons who threw on a lighted squib to protect themselves did not relieve the original thrower of liability. Similarly, a rescuer's intervention is a natural and foreseeable response to danger and does not break the chain, as recognised in Haynes v. Harwood (1935).
In criminal law the same question arises in homicide. Explanation 2 to Section 100 of the BNS (earlier Explanation 2 to Section 299 of the IPC) provides that where death is caused by bodily injury, the person who caused the injury is deemed to have caused the death although proper remedies and skilful treatment might have prevented it. Imperfect medical treatment therefore does not, by itself, break the chain where the injury remains an operating cause.
The doctrine is related to, but distinct from, remoteness of damage, which limits liability to consequences that are not too remote. Examiners ask for its meaning and test whether a given intervening act, such as instinctive self-protection or a rescue, breaks the chain.
What the law says
Whoever causes death by doing an act with the intention of causing death, or with the intention of causing such bodily injury as is likely to cause death, or with the knowledge that he is likely by such act to cause death, commits the offence of culpable homicide.
Illustrations.
(a) A lays sticks and turf over a pit, with the intention of thereby causing death, or with the knowledge that death is likely to be thereby caused. Z, believing the ground to be firm, treads on it, falls in and is killed. A has committed the offence of culpable homicide.
Explanation 2: injury deemed cause of death despite lack of treatment
Earlier law: IPC 299. Culpable homicide
Example
For example, D negligently leaves a loaded truck unattended with the engine running, and a child releases the brake, injuring P. If such interference was foreseeable, the child's act does not break the chain and D remains liable.
For the exam
- Meaning: a new intervening act that breaks the chain of causation.
- Only a free, deliberate and informed, or wholly unforeseeable, act breaks the chain.
- Instinctive acts in an emergency do not break it: Scott v. Shepherd (1773).
- Rescue is foreseeable and is not a novus actus.
- Explanation 2 to Section 100 BNS: failure of treatment does not excuse the person who caused the injury.
1 question in the Law Maker question bank uses this maxim. Practise Law of Torts questions
Related terms
- Res ipsa loquiturThe thing speaks for itself. Where an accident is of a kind that does not ordinarily happen without negligence and the thing was under the defendant's control, negligence may be inferred.
- Volenti non fit injuriaA person who freely and with full knowledge consents to a risk of harm cannot sue for the harm that results. It is a general defence in the law of torts.
- Damnum sine injuriaActual loss or harm caused without the violation of any legal right gives no cause of action in tort.
- Injuria sine damnoThe violation of a legal right is actionable even though the plaintiff has suffered no actual loss. It applies to torts actionable per se, such as trespass and false imprisonment.
- Actus reusThe physical or external element of a crime: the conduct (act or illegal omission), with its circumstances and consequences, that the law forbids.
Further reading
Checked 6 November 2026. Statutory text is quoted from the Bare Acts library, taken from India Code. See the full glossary.