Introduction

In Negligence, a claimant must prove that the defendant's breach of duty owed caused the damage or injury suffered. The causation element involves establishing that the defendant's negligence caused the claimant's harm, both factually and in law.

Factual causation: the 'but for' test

There must be a factual determination as to whether the defendant's actions caused the claimant's harm. This is often referred to as the chain of causation.

• Barnett v Chelsea & Kensington Hospital [1969]1 QB 428

  Facts:

  The plaintiffs were the family of the victim, who had gone to the defendant's hospital but was negligently sent home untreated and died of arsenic poisoning a few hours later. The medical evidence suggested that the victim would probably have died, even if the proper treatment had been given promptly.

  Issue:

  Did the defendant's negligence cause the victim's death?

  Held:

  The defendant 's negligence did not cause the victim's death, the arsenic was the cause. This decision established the but for test: But for the defendant's breach of duty, would the harm to the claimant have occurred? If yes, as in this case, the defendant is not factually liable. However, if the answer is no, then factual causation is satisfied.

• Mc Williams (Cummings) v Arrol & Co [1962] 1 WLR 295

  Facts:

  The plaintiff was the widow of the victim, who fell to his death while working as the defendant's employee. The victim had been working at seventy foot and the defendant did not provide a safety harness, despite a statutory duty to do so. However, there was evidence that the victim would not have worn a harness even had it been provided.

  Issue:

  Did the defendant's breach of duty cause the victim's death?

  Held:

  The House of Lords found that the defendant was not liable as causation was not satisfied. The evidence that the victim would not have worn the safety harness meant but for the defendant's actions the victim would still have died.

Factual causation: proof

A claimant must prove that, on the balance of probabilities, their harm was caused by the defendant's breach of duty.

Factual causation: clinical negligence

Clinical negligence claims may lead to complex causation issues.

• Wilsher v Essex Area Health Authority [1988] AC 1074

  Facts:

  The plaintiff, a premature baby, received negligent treatment at the defendant's hospital and was left blind. However, there were four other different, independent possible causes of his blindness, each alone could have been the cause.

  Issue:

  Did the defendant's negligence cause the plaintiff's injury?

  Held:

  It was for the plaintiff, on a balance of probabilities, to show that the defendant's negligence caused the damage, which he could not do. Statistically each possible cause represented a twenty percent chance of actually being the cause. The House of Lords ordered a retrial on the issue of causation.

• Bolitho v City and Hackney Health Authority [1998] AC 232

  Facts:

  The plaintiff was the mother of the victim, a two year old child, who suffered serious brain damage following respiratory failure and eventually died at the defendant's hospital. The child was taken to the hospital, however a doctor did not attend (due to a technology failure) until after the victim died. The plaintiff argued that the doctor should have attended and carried out a specific procedure, which would have saved the victim's life. The doctor testified that she would not have carried out the procedure even if she had attended and her evidence was backed by a number of medical professionals.

  Issue:

  How did the but for test apply?

  Held:

  The defendant's negligence was based on an omission to act. Therefore, the court had to consider the but for test in a hypothetical situation.

Generally, the courts are cautious about finding against medical professionals for policy reasons. If patients often succeeded in Negligence claims then it may affect a doctor's willingness to treat patients, pioneering new procedures would be unlikely to be tried and the cost of medical care would increase due to higher insurance premiums.

Factual causation: multiple causes

If there are several possible alternative causes then a claimant must show that his harm was caused by the defendant's breach, as in Wilsher v Essex Area Health Authority [1988]. However, cases often involve harm which may have been caused by a combination of a number of factors.

Material contribution approach

The courts have developed the material contribution approach in order to help determine causation where multiple causes contributed to the claimant's harm.

• Bonnington Castings Ltd v Wardlaw [1956] AC 613

  Facts:

  The plaintiff, a steel worker, had contracted a disease caused by exposure to dust from a pneumatic hammer and swing grinders. The defendant, was in breach of a statutory duty to maintain the swing grinders. Therefore, the defendant could only be liable in Negligence if the swing grinders were the cause of the plaintiff's disease.

  Issue:

  What was the cause of the plaintiff's disease?

  Held:

  It was held that, on the balance of probabilities, dust from the swing grinders had materially contributed to causing the plaintiff's disease and on that basis causation could be established.

  Lord Reid: .. It appears to me that the source of his disease was the dust from both sources, and the real question is whether the dust from the swing grinders materially contributed to the disease... [the plaintiff] must make it appear at least that on a balance of probabilities the breach of duty caused or materially contributed to his injury....

• Bailey v Ministry of Defence [2008] EWCA Civ 883

  Waller LJ: .. In a case where medical science cannot establish the probability that 'but for' an act of negligence the injury would not have happened but can establish that the contribution of the negligent cause was more than negligible, the 'but for' test is modified, and the claimant will succeed....

• McGhee v National Coal Board [1973] 1 WLR 1

  Facts:

  The plaintiff contracted dermatitis due to exposure to dust, when cleaning brick kilns for the defendant. Medical evidence suggested that the only way to avoid the dust abrasions was thorough washing of the skin immediately after contact. The defendant negligently did not provide washing facilities on site. However, the medical evidence did not establish whether the lack of washing (which the defendant was liable for) or more generally the exposure (which the defendant was not liable for) was the cause.

  Issue:

  Was sufficient causation proved?

  Held:

  Under the strict all or nothing approach the plaintiff could not prove the defendant caused his dermatitis (Hotson v East Berkshire Area Health Authority [1987]). The plaintiff was also unable to prove that defendant's failure to provide onsite washing facilities materially contributed to his dermatitis (Bonnington Castings Ltd v Wardlaw [1956]). However, the House of Lords found that the defendant's failure to provide onsite washing facilities was a material contribution to the risk of injury and that was sufficient to prove causation.

Therefore, the courts have modified the but for test. This means that a claimant must establish the defendant's negligence either: materially contributed to the harm (Bonnington Castings Ltd v Wardlaw [1956]) or materially contributed to the risk of harm (McGhee v National Coal Board [1973]). In Wilsher v Essex Area Health Authority [1988], the defendant could only be held responsible for one of the possible risk factors and it could not be shown that this increased the risk of the claimant suffering the harm. Therefore, despite the widening of the but for test the claimant was still unable to satisfy the causation requirement.

Divisible injury

The issue arises: to what extent is a defendant who is found to have either materially contributed to the harm or materially contributed to the risk of the harm, liable for damages?

Indivisible injury

In some cases more than one defendant has made a material contribution to the claimant's harm but it is not divisible. For example, in a road traffic accident a single injury suffered may be the result of two different defendant's negligence.

Under S1(1) of the Civil Liability (Contribution) Act 1978, the defendants are jointly and severally liable for the full damages owed to a claimant. This means a claimant may bring a claim for full damages against only one of the defendants. It aids a claimant to recover full damages even if one of the other defendants is insolvent or untraceable. In addition, under S2(1), the courts can apportion liability for damages between the defendants according to their share of responsibility for the harm caused.

Recent developments

A recent decision has been criticised for weakening the test for factual causation and therefore, leaving employers and insurers vulnerable to large claims. However, it can also be seen as providing just recourse for claimants who have suffered serious harm.

• Fairchild v Glenhaven Funeral Services Ltd [2003] 1 AC 32

  Facts:

  The claimants had developed mesothelioma, a cancer, caused by exposure to asbestos. The claimants had worked for several employers and were exposed to asbestos in each job. The defendants were some but not all of the employers. Medical evidence failed to show which of the employers had been responsible for the exposure which led to the cancer. Each defendant argued that the but for test was not satisfied as their breach may have not been responsible for triggering the cancer.

  Issue:

  Could the defendants be held responsible?

  Held:

  The Court of Appeal found that the lack of medical certainty meant that causation could not be proved. However, the House of Lords approved the approach in McGhee v National Coal Board [1973], finding that the defendants had materially contributed to the risk of the claimants contracting the cancer. It also found that mesothelioma was an indivisible injury and therefore, the defendants were jointly and severally liable.

Another controversial decision followed, which appeared to retract the scope of the decision in Fairchild v Glenhaven Funeral Services Ltd [2003].

• Barker v Corus [2006] 2 AC 572

  Facts:

  The claimants contracted mesothelioma working for a number of employers. However, when the case was brought the defendant was the only employer still trading. The defendant argued that if was unfair to impose joint and several liability when their breach had only contributed to the risk of harm. The defendant argued liability should be proportionate only to the extent to which they contributed to the risk (the time that they had employed the claimants and exposed them to the asbestos).

  Issue:

  Could the defendant be held jointly and severally liable?

  Held:

  The House of Lords (majority) held that liability for mesothelioma under Fairchild v Glenhaven Funeral Services Ltd [2003], was for the risk of harm and therefore a defendant's liability should be in proportion to the contribution he has made to the risk of the harm occurring. Furthermore, although mesothelioma was an indivisible injury, the risk of it was divisible and should be reflected in a defendant's liability.

The decision in Barker v Corus [2006], was heavily criticised for limiting a claimant's ability to receive damages in full. Parliament passed the Compensation Act 2006 which effectively reversed the decision for claimants suffering mesothelioma. However, it remains unclear whether the decision will be followed in cases where causation is based on a material contribution to the risk of harm.

Factual causation: loss of chance

The loss of chance concept applies to cases where a claimant is arguing that the defendant's breach caused the claimant to lose a chance, rather than the defendant's breach being a cause of the harm. Therefore, the courts must focus on the outcome of events not the damage which occurred.

In Hotson v East Berkshire Area Health Authority [1987], where the defendant's omission to treat the claimant may have lessened his chance of recovery, the House of Lords decided to use the all or nothing approach. However, it refused to rule out the possibility of successful loss of chance cases in different circumstances.

Factual causation: multiple injuries

If a claimant has suffered one injury or loss followed by another and they are relevant to one another, causation issues can arise.

• Performance Cars v Abraham [1962] 1 QB 33

  Facts:

  The defendant negligently hit the claimant's car and the car required a re-spray. However, two weeks earlier the claimant's car had been hit by another negligent driver. The initial incident meant that the car was in need of a re-spray prior to the incident involving the defendant.

  Issue:

  Could the defendant be liable for the damage?

  Held:

  The Court of Appeal found that the defendant was not liable for the cost of the re-spray because the defendant's breach had not caused the need for the re-spray. Therefore, if a claimant has already suffered the harm, a subsequent defendant is only liable to the extent that he makes the claimant's harm worse.

Similarly, issues can arise in relation to personal injuries.

• Rahman v Arearose Ltd [2001] QB 351

  Facts:

  The claimant had suffered physical injuries after a vicious assault at work, which employer, the first defendant, had negligently failed to protect him from. Subsequently, the claimant was left blind in one eye after receiving negligent treatment, in the second defendant's hospital. Furthermore, the claimant suffered severe continuing psychiatric injury as a result . Medical evidence showed that the complex psychiatric injury could be attributed to the two separate tortious incidents.

  Issue:

  To what extent was each defendant liable?

  Held:

  The claimant's employer was solely responsible for the initial injuries and loss of wages resulting from the attack. The hospital was solely responsible for the blindness. The court found that both were liable for the psychiatric injury. On the basis of the medical evidence, the psychiatric injury was found to be divisible and therefore, the damages were apportioned between the employer and the hospital.

Legal causation: intervening acts

Both factual causation and legal causation must be proved in order to make a claim in Negligence. For the chain of causation to be proved the defendant's breach of duty must have caused or materially contributed to the claimant's injury or loss. However, the chain may be broken by an intervening event. Extrinsic intervening events (nova causa interveniens) may occur or the independent act of someone other than the defendant (novus actus interveniens) may also interfere with the chain of causation. However, an intervening event does not necessarily break the chain of causation.

Third party

The intervening act of a third party may break the chain of causation.

A third party act will not break the chain of causation if the defendant is under a legal duty to prevent that act.

• Stansbie v Troman [1948] 2 KB 48

  Facts:

  The claimant had property stolen from her house, when the defendant, a decorator, left the house unoccupied and unlocked. The defendant was under at duty to secure the property if he left the house.

  Issue:

  Did the intervening act break the chain of causation?

  Held:

  The chain of causation was not broken, the actions of the thief, was the very reason the defendant was under a duty to secure the property.

A third party act will break the chain of causation if it is an unforeseeable consequence of the defendant's own negligence.

• Knightley v Johns [1982] 1 WLR 349

  Facts:

  The defendant was driving negligently which led to his car turning over near the exit from a one-way tunnel. The police officer who arrived at the scene negligently directed the plaintiff to drive back up the tunnel. The plaintiff collided with an oncoming vehicle and was injured.

  Issue:

  Did the intervening act break the chain of causation?

  Held:

  The chain of causation was broken. It was foreseeable the police would attend as a result of the defendant's negligence. However, the gross negligence of the officer was not foreseeable.

  A negligent act of a third party is more likely to break the chain of causation, but not definitely because some errors of judgment are foreseeable.

  Stephenson LJ: .. mistakes and mischances are to be expected....

Therefore, the question of foreseeability, even if the third party was negligent will be decided on the facts of each case.

• Rouse v Squires [1973] QB 889

  Facts:

  The defendant's careless driving resulted in his lorry skidding and blocking two lanes of the motorway. The plaintiff's husband stopped to help the defendant. Another lorry driver, who was also driving negligently, failed to see the blockage soon enough and killed the victim.

  Issue:

  Did the intervening act break the chain of causation?

  Held:

  The Court of Appeal found that the chain of causation was not broken, as it was reasonably foreseeable that other drivers may arrive at the scene too fast to stop. Both the defendant and the second driver had made a material contribution to the indivisible injury. Under the Civil Liability (Contribution) Act 1978 the court apportioned liability between them.

An instinctive intervention, by a third party, may not break the chain of causation if it is a foreseeable reaction.

• Scott v Shepherd (1773) 2 Wm Bl 892

  Facts:

  The defendant threw a lighted squib into a crowded market. Two other individuals picked the squib up and threw it away from themselves and their stalls. The squib eventually exploded in front of the plaintiff, who lost his eye.

  Issue:

  Did the intervening acts break the chain of causation?

  Held:

  The intervening acts did not break the chain of causation, as the third parties were acting instinctively to the danger posed by the defendant's act.

  De Grey CJ: .. all that was done subsequent to the original throwing as a continuation of the first force and first act.. any innocent person removing the danger from himself to another is justifiable... acting under a compulsive necessity for their own safety and self-preservation....

Claimant

A claimant's own act may break the chain of causation.

A cliamant's own act may be a novus actus interveniens if he acts unreasonably.

• McKew v Holland & Hannen & Cubitts [1969] 3 All ER 1621

  Facts:

  The plaintiff injured his leg at work, due to his employer's negligence (the defendant). A few days later, the plaintiff was descending some steep steps without a handrail. He lost control of his leg and fell down the stairs, severely fracturing his ankle.

  Issue:

  Did the plaintiff's intervening act break the chain of causation?

  Held:

  The plaintiff's act did break the chain of causation because he took an unreasonable risk.

  Lord Reid: .. if the injured man acts unreasonably he cannot hold the defender liable for 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....

A claimant's act of carelessness may not always be considered so unreasonable as to break the chain of causation. However, it may be viewed as contributory negligence on the claimant's part.

• Spencer v Wincanton Holdings Ltd [2009] EWCA 1404

  Facts:

  The claimant was injured at work, resulting in his leg being amputated. The defendant was liable was for this injury. Several months later, the claimant had an accident, trying to use his new prosthesis, which meant that he would be permanently confined to a wheelchair.

  Issue:

  Did the claimant's intervening act break the chain of causation?

  Held:

  The claimant's act did not break the chain of causation. However his damages were reduced as contributory negligence was accepted as a partial defence.

  Lord Sedley: .. Like the amputation, the fall was... an unexpected but real consequence of the original accident, albeit one to which [the cliamant's] own misjudgement contributed....