Williams v Bermuda Hospitals [2016] UKPC 4 – Material Contribution in Clinical Negligence

June 15, 2016

By Bill Braithwaite QC

For those interested in clinical negligence, the Privy Council gave a very helpful decision in relation to causation on the 25th January 2016 – Williams v Bermuda Hospitals [2016] UKPC 4. I’m a great believer in simplifying legal issues, and I’ve always thought that this area, encompassing material contribution, needed a breath of fresh air.

In Williams, the Claimant went to the local hospital emergency department in Bermuda, complaining of abdominal pain. He was suffering from acute appendicitis. Later that day he had an appendectomy, but there were complications allegedly the result of negligent delay in his treatment.

On arrival at A&E, the emergency doctor appropriately ordered a CT scan of the abdomen to determine whether the Claimant was suffering from appendicitis or some other condition. There was a delay of over five hours before the scan was performed, and a doctor did not receive a report on the scan until about two hours later.

During that time, his appendix had ruptured, and sepsis from the ruptured appendix caused injury to his heart and lungs. The rupture of the appendix would not have been an instantaneous event, but a gradual process. The scan request had not been marked as urgent, which was the main cause of complaint. The trial judge’s factual finding was that the failure to order a scan on an emergency basis led to a delay of between 4 hours 15 minutes and 2 hours 20 minutes in the start of the relevant operation. He decided that, had the CT scan been obtained and interpreted promptly, the complications might have been avoided, but he was not satisfied that they probably would have been. He therefore decided that there had been negligence but that the Claimant had not proved that the culpable delay caused the complications.

The Bermudan Court of Appeal reversed the judge’s decision on causation.


The Board of the Privy Council started by analysing the important case of Bonnington, decided in 1956. In that case, the claimant contracted pneumoconiosis from the inhalation of particles of silica; most of the dust originated from the operation of pneumatic hammers, but some of it escaped from swing grinders. The former involved no negligence, but the latter resulted from a breach of statutory duty. The House of Lords started by re-stating that the employee must always prove his case by the ordinary standard of proof i.e. he must prove that, on a balance of probabilities, the breach of duty caused or materially contributed to his injury. Turning to causation, though, they held that causation was sufficiently established because the claimant’s disease was caused by a gradual accumulation in his lungs of minute particles of silica and, if that material comes from two sources, it cannot be wholly attributed to one source or the other. It is not correct then to ask which was the most probable source of the respondent’s disease, the dust from the pneumatic hammers or the dust from the swing grinders. The source of the disease was the dust from both sources and the real question is whether the dust from the swing grinders materially contributed to the disease. As the dust from the swing grinders did contribute, causation was established.

What is a material contribution must be a question of degree, but it must not be negligible.

Because this article is about clinical negligence, it isn’t appropriate to delve further into industrial disease law; suffice it to say that in later cases it has been the accepted view that pneumoconiosis is a “divisible” disease e.g. Sienkiewicz v Greif (UK) Ltd [2011] 2 AC 229.

The judges in Williams went on to compare and contrast Hotson v East Berkshire Health Authority [1987] AC 750, which was very much an “either or” case. The claimant fell from a tree and fractured his left femoral epiphysis. He was taken to hospital where, for several days, his injury was not properly diagnosed or treated. He suffered avascular necrosis of the epiphysis, leaving him with a permanent disability. The House of Lords held that the avascular necrosis must have been caused either by irreparable rupture of the blood vessels to the epiphysis at the moment of the fall, or by later pressure within the joint from bruising or internal bleeding. There was no room for finding that the avascular necrosis was caused by a combination of the two factors. The House of Lords held that, unless the claimant proved on a balance of probabilities that the delay in treatment was at least a contributory cause of the avascular necrosis, he failed on causation. As the judge had decided that the fall was the sole cause of the necrosis, the claim was bound to fail.

The Privy Council also considered McGhee v National Coal Board [1973] 1 WLR 1, in which Lord Simon said that where, on the balance of probabilities, an injury is caused by two (or more) factors operating cumulatively – one (or more) of which is a breach of duty – it is immaterial whether the cumulative factors operate concurrently or successively.

Material Contribution

As a matter of principle, successive events are capable of each making a material contribution to the subsequent outcome. A claim will fail if the most that can be said is that the claimant’s injury is likely to have been caused by one or more of a number of disparate factors, one of which was attributable to a wrongful act or omission of the defendant. In Wilsher v Essex Area Health Authority [1988] AC 1074, the claimant was born prematurely and, as a result of clinical negligence, he was given too much oxygen. He developed retrolental fibroplasia, which can be caused by various factors, one being an over-supply of oxygen. The House of Lords held that it was not enough to show that the defendant’s negligence added to the list of risk factors to which the claimant was exposed. They distinguished the case from Bonnington, because in that case the injury was caused by a single, continuous process.

In this case of Williams, the injury to the heart and lungs was caused by a single process, sepsis from the ruptured appendix. The sepsis developed incrementally over a period of approximately six hours, progressively causing myocardial ischaemia. The sepsis was not divided into separate components causing separate damage to the heart and lungs. Its development and effect on the heart and lungs was a single continuous process. Because that process continued for a minimum period of 2 hours 20 minutes longer than it should have done, the Board held that it was right to infer on the balance of probabilities that the negligence had materially contributed to the process, and therefore materially contributed to the injury.

Bailey v Ministry of Defence [2009] 1 WLR 1052

When I was giving a lecture recently on clinical negligence, I was asked whether Bailey v Ministry of Defence [2009] 1 WLR 1052 was still good law in the light of Williams, and so it was nice to be able to answer with clarity, because the Privy Council dealt with it.

In Bailey, the claimant underwent a surgical procedure, following which her treatment was negligent. As a result, she had to undergo further major procedures which should not have been necessary, and which led to her being in a weakened state. Later, in ITU, she vomited in her sleep and aspirated the vomit, causing her to suffer a cardiac arrest and hypoxic brain damage. The judge decided that the Claimant’s weakened state was partly due to pancreatitis for which the hospital was not responsible, and partly due to their negligence i.e. that there were two components of her weakness. He could not say whether the contribution made by the negligent component was more or less than that made by the non-negligent pancreatitis, but he did say that each contributed materially to the overall weakness and it was the overall weakness that caused the aspiration.

The Privy Council thought that the judge was right in his approach and conclusion, but they did disagree with the Court of Appeal which had thought that the case involved a departure from the “but-for” test. They said that the fact that her vulnerability was heightened by her pancreatitis no more assisted the hospital’s case than if she had an egg shell skull.

Having the law set out so clearly by the judges makes it easier for advocates to prepare claims; it is always important to know what you would like to prove in a case, and knowing that a continuous process makes it easier to win is a good start to any investigation.