Medico-legal Minder

The recent decision in Williams v Bermuda Hospitals Board [2016] UKPC 4 is an important statement of the principles of the doctrine of ‘material contribution’ in clinical negligence cases. Although it is a Privy Council decision on appeal from Bermuda, the same judges make up the Supreme Court in our jurisdiction, and the decision is effectively binding on the courts of the UK.

Mr Williams had gone to an A&E Department complaining of abdominal pain. He had appendicitis. A CT scan was planned but was not carried out expeditiously. There were significant delays in diagnosing and treating Mr Williams. During the delay, his appendix ruptured and sepsis developed. The sepsis caused myocardial ischaemia.

The judges held that the MI was caused by sepsis of which there was “guilty” sepsis attributable to the negligent delay and “innocent” sepsis which had already begun irrespective of the delay in diagnosis and treatment.

Readers may recall the case of Hotson[1], the boy who fell from a tree and fractured his femoral epiphysis. There was negligent delay in diagnosis and he developed avascular necrosis. His claim fell because there was a 75% chance of that same outcome in the absence of the negligence and delayed diagnosis, and therefore it could not be proved on the balance of probabilities that the avascular necrosis was caused by the clinical negligence. In Williams however it could not be said that the MI would probably have occurred in any event. Mr Williams succeeded on causation by proving that, on the balance of probabilities, the negligence had materially contributed to the developing sepsis and had therefore materially contributed to the MI.

Williams demonstrates that a defendant’s material contribution need not be concurrent with any non-negligent cause. In Mr Williams’ case, the sepsis attributable to the defendant’s negligence developed after sepsis had already begun to develop. The causes can be either concurrent or consecutive or both. However while the law allows for multiple, cumulative causes it does not allow causation to be established where there are multiple, possible causes, as in the case of Wilsher[2] (multiple possible causes of birth defect, none of which could be shown to be more than 50% probable).

What appears to be a case requiring material contribution in order to be able to establish causation may not be. In Williams it was said that the earlier case of Bailey v MOD[3], previously considered an example of material contribution, was in fact an example of the ‘egg-shell skull’ principle. The non-negligent condition of pancreatitis in that case was a pre-existing vulnerability on which the subsequent negligent lack of care caused, on the balance of probability, the cardiac arrest.

The medical expert is advised to seek guidance from the instructing solicitor in any case in which traditional causation is unclear and material contribution might be relevant.

[1] Hotson v East Berkshire Area Health Authority [1987] AC 750,

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

[3] Bailey v Ministry of Defence [2009] 1 WLR 1062

[Who or what is medico-legal minder? Terms and conditions apply]

In Hayden v Maidstone & Tunbridge Wells NHS Trust [2016] EWHC 1121 (QB) the judge was faced with an application made at the very last minute by the defendants for permission to rely on surveillance evidence recently obtained by them and which they considered undermined the claimant’s case. The possible benefit of such evidence had been ‘sign-posted’ by the defendants’ pain expert, and he had been asked to review the edited film once it was obtained. He found this film supportive of his criticism of the claimant’s case.

One of the perhaps not very attractive arguments put forward by the defendants as to why, despite the last minute disclosure, the surveillance evidence should be admitted was that it would be difficult for an expert who has seen the surveillance evidence to put it out of his mind and to make no reference to it when he came to give evidence and to be cross-examined. The judge did not consider that that could be a reason for a court to feel obliged to admit the evidence.

‘Experts are familiar with the need not to refer to the content of any “without prejudice” discussions with their counterparts and the same applies, albeit doubtless with less familiarity, to [the parties themselves] who have to be advised by their lawyers not to make reference when giving their evidence to what was said during “without prejudice” negotiations.’ (para 40)

So experts can be expected, when giving evidence of their opinion, to put out of their minds material evidence of which they have knowledge. The judge continued:

‘When, inadvertently, some forbidden material “slips out” during the course of giving evidence, all judges are familiar with the need simply to put such material out of their mind.’

That is part of a judge’s ‘training’. But what if, despite being made aware of the need to ‘forget the evidence’, the expert still makes reference to it in the course of evidence?

‘Where some obviously deliberate attempt is made to refer to such material, it will weigh heavily in the evaluation of the witness who makes such an attempt.’

So the witness is likely to lose credibility with the court if the genie is not placed firmly back in the bottle while giving evidence.

In Hayden the judge therefore found that the difficulty of ‘forgetting’ that which was known was not a ‘determinative consideration’ in the exercise of his discretion as to whether or not the evidence should be admitted. Indeed the judge found this argument ‘deeply unattractive’. (para 41)

Given an expert’s duties and the requirements of the Civil Procedure Rules, the position could become somewhat more complicated, if for example the expert saw surveillance evidence, found it material, and altered his or her opinion. The expert’s report must state the substance of all material instructions, whether written or oral, on the basis of which the report was written (CPR 35.10(3)); must contain a statement setting out the substance of all facts and instructions which are material to the opinions expressed in the report or upon which those opinions are based (35 PD 3.2(3)); and if, after producing a report, an expert’s view changes on any material matter, such change of view should be communicated to all the parties without delay, and when appropriate to the court (35 PD 2.5).

An expert witness must understand that, in certain circumstances, there are some matters which may be within the expert’s knowledge which may not be relied upon in the course of a trial – facts which the expert is under a duty to forget for the purposes of the trial. Thankfully such instances will be out of the usual, and these are matters on which the expert must seek advice from the instructing lawyers.

In fact, in Hayden, the judge admitted the surveillance evidence despite the defendants’ dilatory actions although ‘with considerable misgivings’. By the time that the application (to admit the surveillance evidence) was finally to be determined the claimant and one of her expert’s had reviewed the edited film, and the judge stated that he was influenced in his decision ‘by the fact that the claimant and one of her principal medical experts have been able to answer (… at least at face value) the new material and [the defendants’ expert’s] analysis of it in a strong fashion.’ Moving from the Arabian Nights to a sporting analogy he concluded that ‘the playing field has, in my view, remained level.’ (para 56)

[Who or what is medico-legal minder? Terms and conditions apply]