What constitutes a novus actus interveniens?
Roger Cooper considers the question of unreasonable conduct on the part of a claimant so as to break the chain of causation in light of Sparrow v Andre
On the morning of 10 February 2013,
Mr Craig Sparrow (the claimant) was manoeuvring his car in a crowded car park at a club in London when Mr Arnaud Andre (the defendant) negligently reversed his car out from a space and into collision with Sparrow's car, so that some relatively minor damage was done. Sparrow got out to examine the damage, leaving his children in the car. He omitted to apply the brake or to put the car in 'park' mode so as to prevent it from moving.
Andre moved his car, whereupon Sparrow's car began to roll down a slope. Fearing for the safety of his children, Sparrow tried to arrest the motion of his car as it gained speed down the slope. He tried to gain a better footing but the car took him with it and his left leg became trapped between the car and a metal post. Such was the extent of the injury to his leg that it later had to be amputated.
At trial (Sparrow v Andre  EWHC 739 (QB)), Mrs Justice Lang found that the initial collision between the vehicles had been caused by the negligence of Andre in failing to keep a proper look out as he reversed. The judge also found that the initial incident was the cause of the claimant's injuries as it satisfied the 'but for' test. The question remained, however, whether the chain of causation was broken by Sparrow's failure to apply the brake - in other words, was there a novus actus interveniens?
The principles and authorities to be applied in such cases were reviewed recently by Lord Justice Christopher Clarke in Scott v Gavigan  EWCA Civ 544. The starting point is often the speech of Lord Reid in the Scottish case of Mckew v Holland & Hannen & Cubitts  3 All ER 1621. In that case the pursuer (the claimant in England and Wales) had sustained a leg injury caused by the negligence of the defender, but then was injured again as he leapt while descending some stairs.
Lord Reid said: 'In my view the law is clear. If a man is injured in such a way that his leg may give way at any moment he must act reasonably and carefully. It is quite possible that in spite of all reasonable care his leg may give way in circumstances such that as a result he sustains further injury. Then that second injury was caused by his disability which in turn was caused by the defender's fault. But if the injured man acts unreasonably he cannot hold the defender liable for his injury caused by his own unreasonable conduct. His unreasonable conduct is novus actus interveniens. The chain of causation has been broken and what follows must be regarded as caused by his own conduct and not by the defender's fault or the disability caused by it.'
So unreasonable conduct on the part of the claimant can break the chain of causation, but what amounts to 'unreasonable' in this context? This was a matter of comment by Lord Justice Sedley in Spencer v Wincanton Holdings Ltd  EWCA Civ 1404. Drawing upon the judgment of Lord Nicholls in Kuwait Airways v Iraqi Airways  UKHL 19, he reminded us that loss in tort depends on determining first whether the tortious conduct causally contributed to the claimant's loss and, if so, the extent to which the wrongdoer ought to be held liable for such loss. This latter question necessarily involves a value judgement.
Question of fairness
Sedley LJ noted that the term 'unreasonable'
is a protean adjective whose nuances range
from irrationality at one extreme to simple
lack of caution at the other. The purpose of identifying unreasonableness in this context, however, is to identify the point at which the law regards a consequence as being too remote. It is ultimately a question of fairness, according to Sedley LJ.
It can be argued, however, that the concept of negligence is also protean. A motorist guilty of a momentary lapse of concentration would be liable to the same degree as a motorist guilty of a reckless course of driving if the damage sustained by the innocent road user happened to be identical. Fairness might suggest that a reckless motorist should be liable for more than a merely careless one, but that is not the case. Once the threshold of negligence is crossed, it does not matter if the wrongdoer was a little bit negligent or a lot negligent.
But when it comes to the question of unreasonable conduct on the part of a claimant so as to break the chain of causation, those same concepts of fairness do come into consideration. It is not just a question of whether the claimant's action was the proximate cause of the loss; it demands a value judgement based on fairness.
Sedley LJ continued: 'Fairness, baldly stated, might be thought to take things little further than reasonableness. But what it does is acknowledge that a succession of consequences which in fact and in logic is infinite will be halted by the law when it becomes unfair to let it continue. In relation to tortious liability for personal injury, this point is reached when (though not only when) the claimant suffers a further injury which, while it would not have happened without the initial injury, has been in substance brought about by the claimant and not the tortfeasor.'
Returning to Sparrow, how were these principles applied in his case? The trial judge found that Andre should fairly and reasonably be held liable for the whole of Sparrow's injuries, including the amputation. Although Sparrow was negligent in not applying the brake, it was secondary to and arose in the context of Andre's primary breach,
so held the judge.
Nevertheless, Sparrow was found guilty of contributory negligence and a reduction in
his damages of 60 per cent was made. Is this consistent with the principles set out above?
By negligently failing to apply the brake, surely Sparrow was acting unreasonably? If the rolling car had caused injury to Sparrow's children, then he would inevitably have been liable for those injuries on account of his failure to apply the brake, irrespective of any liability of Andre.
If his unreasonableness gave rise to contributory negligence, why did it not also break the chain of causation? This tension was recognised by Lord Justice Aikens in Spencer: 'The line between a set
of facts which results in a finding of contributory negligence and a set of facts which results in a finding that the "unreasonable conduct" of the claimant constitutes a novus actus interveniens is not, in my view, capable of precise definition… each case will depend on the facts and… the court will have
to apply a value judgement to the facts as found.'
It is clear, therefore, that the judgment in Sparrow's case was indeed consistent with authority. Moreover, it did justice to the parties
in that Sparrow was not entirely deprived of compensation in respect of a grievous injury,
but neither did he receive full compensation when his injury was caused at least in part by his own negligence. Perhaps the finding of contributory negligence was a little harsh at 60 per cent when his negligence was committed in a moment as he reacted to the shock of his car just having been hit by another.
Since the decision as to what amounts to a novus actus and what amounts to contributory negligence is simply an exercise of judgement on the facts as found, it becomes nigh on impossible to predict with real confidence the outcome of such cases in advance.
Further, such determinations at trial will be
very difficult to appeal successfully as a generous ambit would be accorded to the judge at first instance, given their advantage in having heard from the witnesses first and being so well acquainted with the facts.
It is not uncommon in personal injury cases for an injured claimant to suffer from a second injury and to allege that the second injury was simply a consequence of the first. For example, a claimant who has suffered a knee injury may seek to argue that their injured knee subsequently gave way, causing them to fall and sustain a wrist injury.
Rather than simply accepting that proposition as necessarily correct, defence practitioners may wish to make further enquiries to see whether there are grounds to argue that the activity being pursued by the claimant at the time of the second injury was unreasonable. This will then open
up an opportunity to argue for a reduction in respect of contributory negligence, or even that the second accident was the consequence of a novus actus interveniens.
Roger Cooper is a barrister practising from Parklane Plowden @ParklanePlowden www.parklaneplowden.co.uk