January 17, 2022

Novus Actus Interveniens

Law of torts


The link between the facts and the liability is of the utmost difference in the Law of Torts. To establish causation, there must be a chain of events (factual causation) that lead to a cause of action (legal causation) brought by a plaintiff. There are various factors that affect this determination, one of it is ‘Novus Actus Interveniens’. The phrase ‘Novus Actus Interveniens’ is a Latin legal maxim that stands for ‘new intervening act’. In the Law of Delict 6th Edition, Neethling states that a Novus Actus Interveniens is “an independent event which, after the wrongdoer’s act has been concluded either caused or contributed to the consequence concerned”.[1]

Thus, an intervening act leads to a breakage in the cause-effect relation of the act that harmed the plaintiff. It is used as a defence by defendant to negate or reduce his liability. For ascertaining, when can the act be termed as ‘intervening’, one has to consider two tests.

First is the test of foreseeability which refers to whether such a happening could have been anticipated by the defendant so to know the degree of extended harm it may lead to.

Second is the test of direct damage that comes into play when one has to check if the act was a direct result of the act that caused the injury on the first instance. If the answer for both these tests is affirmative then the defence fails.

Aspects of the Act

1. Intervening acts that do not negate the defendant’s liability in terms of the consequent harm:

This defence cannot be pleaded very easily by the defendant parties as the causation link is often sufficed on the basis of the facts that indicate, that despite the intervening acts, the chain of causes wasn’t broken as the injury suffered by the plaintiff is still a direct implication of the defendant’s act. The test to determine whether an intervening act disrupted the chain of cause or not, one needs to take into consideration whether the injury caused by it can be distinguished from the ‘original act of harm’.

To this effect, certain precedent provide a clearer picture, some of which are enumerated below:

The Oropesa[2]

The plaintiff’s ship (Manchester Regiment) was damaged due to a collision with the defendant’s ship (the Oropesa). In an attempt to discuss the situation with the defendant ship’s captain, 50 crew members and then the captain along with another 15 members attempted to travel across which resulted in the overturning of the boat they were riding, causing death of the captain and several members of the crew. The dependents of the deceased sued the defendant. The court ruled that the death caused was an implication of the original harm and there were no intervening acts in between.

Scott V. Shepherd [3]– Famous Squib Case

In this case, D threw a lighted squib into a crowd which landed on X. He (X) also threw it farther where it landed on Y who again repeated the act which ultimately affected P as there was explosion caused by the ignited squib, leaving P blinded in one eye. The court ruled that irrespective of the intervening acts of X and Y, the harm caused to P was a result of the action that was initiated by and was because of D. His defence for ‘Novus actus interveniens’ was rejected on the ground of his act being ‘causa causans’.

In Wright v Lodge & Shepherd[4]

In this case, the plaintiff had suffered damages due to the collision caused by the reckless driving of Mr. Lodge. The second defendant Miss Shepherd had negligently left her lorry at the motorway which further increased the extent of damages suffered by the plaintiff. In the suit brought by the plaintiff, the court while acknowledging that Miss Shepherd’s act did constitute an intervening act however the it was Mr. Lodge, who was at much fault and thus the liability lies on him largely. Simultaneously, the court also stated that the pecuniary compensation for damages will be divided in a ratio of 1:9 (10%/90%) between defendant 2 and defendant 1.

2. Intervening acts that negate totally or partially the defendant’s liability in terms of the consequent injury:

They can be further sub-categorised as – third-party acts that breaks the cause-effect chain (to be determined on factual basis), act of nature and the acts of plaintiff.


If an unreasonable act is undertaken by a third-party in response to a negligent harm, that will break the chain of causation. The same was stated in the following case:

Haynes V. Harwood[5]

D had left his unattended horse van on streets which amused the children in the milieu and they started pelting stones at it, as a result of which it went haywire and started running. A policeman intervened in the scene to stop the horse but suffered injuries as a result who then sued D for the same. The court held that D would not be responsible for the act of the children that lead to the harm suffered by the plaintiff as the same act could be construed as ‘intervening’ cause.


Acts of nature better known as ‘Act of God’, can be anything that is neither under any human control nor foreseeable such as storm, earthquake. The acts of nature are an important constituent of ‘Novus actus ineteveinies’ due to the fact that they can’t be predicted or anticipated which is why the defendant cannot be made liable for any damages arising out of it. This principle was held in the case of:

Carslogie Steamship Co Ltd v Royal Norwegian Government[6]

In this case, the plaintiff had suffered damage to his ship as a result of collision with the defendant’s vessel due to his (defendant’s) negligence. This damage was further exacerbated due to a storm in the sea. The court in this case held that the defendant’s liability can only be accorded till the point of the ‘harm arising out of his own actions’ i.e. the defendant has to compensate only for the damage caused by the collision and not for the one caused by the storm. The court observed that ‘harm caused by storm was incidental in nature and cannot be traced back to the original harm caused by collision’.


Even though the acts of the defendant lead to the initiation of the cause chain which in most cases cannot be affected by the plaintiff However, there are certain instances when the plaintiff does an act that aggravates the original harm caused by the defendant in an extremely unforeseeable extent which leads to diminishing the effect of the damage caused by the defendant. This reason behind it is that the chain of events is broken in such a way that it is difficult to impute liability. The same was reiterated in :

McKew v Holland & Hannen & Cubitts[7]

The plaintiff had to bear an injury due to his employer’s negligence which was further aggravated by the strenuous activity undertaken by the plaintiff such as attempting to climb the stairs without a handrail while his back, hips and legs were injured and unable to support such an activity.

As a consequence, his legs gave way in the process and he fell down the stairs fracturing his right ankle. He also had to bear a permanent disability because of the incident. The plaintiff bought an action against the defendant for the injuries and disability he suffered. The court in this case ruled that the defendant will only be liable for his negligence and not for the injuries and disability that were the result of plaintiff’s own actions.

Difference Between Novus Actus Interveniens And Contributory Negligence

Novus Actus Interveniens is often confused with contributory negligence owing to the fact that it covers within its ambit, acts that can be termed ‘intervening’ on the part of the plaintiff as mentioned supra. For the sake of eliminating this discrepancy, the time when the omission/commission on the part of the plaintiff affects the chain of causation is considered. As in, when this act coincides with the ‘original harm’ caused by the defendant then it may be attributed as ‘contributory’ and when it takes place post the happening of the ‘original harm’ then it may be attributed as ‘an act breaking the causation change’.

For instance: At 10 pm, Mr. A was walking on the wrong side of the road with very low light settings and Mr. B was coming from the opposite direction without his turning on his headlights which leads to a collision which caused hurt to Mr. A. This is a classic example of contributory negligence. However, if we suppose that Mr. A wasn’t walking on the wrong side of the road and initially it was only Mr. B at fault but post-accident, Mr. A did something that aggravated his injury to an extent that it could not have been anticipated then it is a ‘Novus Actus Interveniens’.

Application in Ascertaining Medical Negligence

The defence is now increasingly being used in cases of all kinds of negligence especially Medical Negligence. One of the landmark cases in this respect was:

MEC Health, Eastern Cape v Mkhitha[8]

In this case, the plaintiff had suffered injuries in motor vehicle collision in June of 2011. She was admitted into the Nelson Mandela Academic Hospital to the Bedford Orthopaedic Hospital (BOH) to undergo surgery for her injuries however there was a ‘dereliction of duty’ on the part of the hospital staff as they did not carry out the required X-rays of the patient’s leg, which is why her right femur couldn’t heal properly. The plaintiff brought a suit against both the RAF (Road Accident Fund) and the hospital for damage suffered by her.

After contentions were raised by both sides, the court reached the decision that the even though, it was the actions of RAF’s insured driver that lead to the initiation of the injury suffered by her but the negligence of the hospital in providing inapt medical aid was not something that could have been anticipated by the RAF nor it could not be termed as an ‘independent intervening act’ as it did lead to the disruption of chain of causes that altered the liability of the RAF significantly.

Relevance in Law

The defence is an important link in establishing factual and legal causation. There has been a development in its usage as per the evolution of case precedents concerning it. Apart from being pleaded as a defence by the defendant, the term also allows the plaintiff to bring a subsequent/second cause of action against the party that commits the intervening act that results in aggravation of his/her injury/damage.

For more notes on Law of torts, Click Here.

For law notes, Click Here.


[1] ‘Novus actus intervenes’ (Lexology, 24 February 2014)

[2] [1943] 1 All ER 211

[3] [1773] 96 Eng. Rep. 525

[4] [1993] 4 All ER 299

[5] [1936] 1 KB 146

[6] [1952] AC 292

[7] [1969] 3 All ER 1621

[8] (1221/15) [2016] ZASCA 176

Author Details: Prachi Tandon (Institute of Law, Nirma University)

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