Mather v Ministry of Defence

This is an action brought by the Claimant as a former employee of the Defendant for personal injuries in the nature of multiple sclerosis (“MS”) and psychiatric injury which he alleges has been suffered as a result of his use of organic solvents in the course of his work as a painter and finisher with the RAF between 1989 and 2003. His claim is that his injuries have been caused by the Defendant’s breach of duty, negligence and breach of statutory duty (the Control of Substances Hazardous to Health Regulations “COSHH”). The Defendant denies breach of duty of care and negligence and/or breach of statutory duty, causation or damage for which it is responsible. The Defendant also says that the claim is statute barred.

Very central to the issues in the case is the question of whether the Claimant can show that his MS was caused by his work for the Defendant. This includes two issues, namely first whether exposure to the organic solvents to which the Claimant was exposed can cause MS, and, if so, (b) whether it did cause his MS. The Defendant expresses confidence about its defence to the claim and believes that it will succeed on causation which would render the trial of the other issues otiose. To that end, it seeks to have tried causation as a preliminary issue in one of two ways, that is either by

The Claimant, whilst willing to hive off quantum, views the case as much more nuanced than the Defendant. The Claimant says (though not in these words) that a preliminary issue is an intended short cut which is liable to increase rather than decrease complexity and expense.

The matter comes before the Court in the following circumstances. On 20 July 2020, the Defendant issued an application to have causation tried as a preliminary issue. On 20 November 2020, Master Thornett released that application to be heard by the trial judge “drawing upon their wider case management powers as if a trial judge hearing the case on a pre-trial review”. Since the case is unlikely to be tried until 2022, he did not mean that the application would necessarily be heard by the trial judge, but that it should be heard by a Judge of the Queen’s Bench Division who would be used to dealing with long or complex trials.

There is also before the Court an application of the Claimant for permission to rely upon an addendum report from Professor Cherrie, the Claimant’s occupational hygiene expert, about possible carcinogenesis of organic solvents. In view of the way that application went, I shall simply make some brief reference to it at the end of this judgment.

The Court has been assisted by full skeleton arguments from the Claimant and the Defendant supplemented by the high-quality oral submissions of Ms Harrison QC for the Defendant applicant and Mr Rawlinson QC for the Claimant respondent both with the assistance of junior Counsel. I heard oral argument on 10 March 2021 for most of a court day, and this is the reserved judgment.

This Judgment shall consider causation by separating factual background, medical causation and applicable law.

The Defendant says that there is considerable oral evidence regarding the solvents used and the level of exposure. In connection with breach of duty, there will be issues regarding how the chemicals were regulated and any permitted levels of exposure. The Defendant submits that the best possible case of the Claimant comes from its occupational hygiene expert, Professor Cherrie. The Claimant’s first statement identifies the chemicals used and the conditions in which he worked: see paras. 4-10, 45-85. The working period of the Claimant with the Defendant was between 1989 and 2003, but the Defendant says that one can ignore the period from 1994 because the occupational hygiene experts agree that from 1994, the exposure to solvents “…would most likely have complied with the standards in place at that time”: see joint statement at paras. 7-8. It also says in any event that as regards the period from 2000, the evidence is irrelevant. This is because it appears that the Claimant contracted MS from 2000, and thus no further exposure after 2000 could be taken to be causative or contributory. The Defendant says there is no evidence to the effect that once a person has MS that continued exposure to solvents could affect the progress of the disease.

The Defendant says that the case does not depend as regards causation on hearing from 25 lay witnesses and two occupational hygiene experts. That is relevant to duty of care, but not to the question whether the exposure to solvents may have caused the injuries and, if so, whether it did cause them. The need for that evidence could be avoided by taking the case of the Claimant at its highest. The Defendant has sought to do this by reducing the evidence of Professor Cherrie on exposure in a table so that this may form the basis for a set of assumed facts either for the trial of a preliminary issue or the determination of causation as a separate first tranche of a trial. It seeks to replicate the relevant parts of Professor Cherrie’s tables 3-5.

The Claimant says that it is not accepted that no further exposure after 2000 could be relevant to the progress of the MS. The case on both sides may be based on assumptions or burden of proof. The Claimant relies on the absence of evidence that continued exposure could cause the progression or accelerated progression of symptoms of MS, which is premised on the Defendant bearing the onus of proof in this regard. The Defendant says that it is for the Claimant to prove this. Whichever is the case, it can be expected that this is an issue which might be addressed before trial by the clinical and epidemiological experts. In the meantime, the Claimant objects to an assumed fact that exposure post-2000 can be taken out of the equation in a causation trial.

Further, the Claimant also objects to an assumed fact that exposure after 1994 is irrelevant because of the evidence that this might have been below certain workplace threshold limits. For the purpose of medical causation, the Claimant says that the Court has to consider the total amount of exposure. There will be an argument on duty of care that the threshold limits are not determinative: if it were reasonably practicable for an employer to expose an employee to a level of exposure below the standard levels, then the Claimant submits that it would be a breach of the duty of care to expose the employee above the lowest level reasonably practicable. There is therefore a question of law as to whether any duty (as per the Defendant) was no higher than to keep the exposure below certain recognised standards, or (as per the Claimant) the duty was to keep exposure to the lowest level reasonably practicable (and even below the recognised standards). Thus, the degree of exposure will require consideration not only in respect of breach of duty, but also in respect of causation. The Claimant submits that this determination will require consideration of lay evidence and occupational hygiene expert evidence.

In any event, the Defendant submits that the precise details about exposure levels are not critical because the expert medical evidence is incapable of proving causation as a matter of principle. In that regard, the Defendant’s case is summarised at para. 13 of Counsel’s skeleton argument that:

“(a)

MS is a disease which is generally regarded as of unknown aetiology; and (b) when asking the question of whether an exogenous environmental factor has caused a naturally occurring disease (such as MS or cancer), the first step is to prove that the exogenous factor in question is capable of causing the disease. That requires proof that the exogenous factor more than doubles the risk of the index condition…. If it were otherwise, endogenous factors could provide a complete explanation for the manifestation of the disease. The Defendant’s position is that there is no probable let alone provable, link between organic solvents and the Claimant’s MS

[see e.g. Professor Silman’s evidence in the Joint Statement, at page 2, 3rd and 5th bullet points].”

The Defendant draws attention to most of the Claimant’s evidence falling short of showing doubling of the risk: see point 4 of the joint statement of Professor Seaton for the Claimant and Professor Silman for the Defendant. Dr Schmierer does opine that organic solvents more than doubled the Claimant’s risk of MS, but he is relied upon as a clinical rather than an epidemiological expert and he defers to the experts on epidemiology with whom his opinion conflicts. The Defendant says that the causative nexus cannot be proven by clinical experience. It says that whether individual causation can be proven on clinical grounds is a question of law which is suited to determination either as a preliminary issue or as an isolated preliminary point in a trial.

The Claimant says that the Court is entitled to consider the clinical evidence and to give due weight to the evidence of Dr Schmierer. In any event, the Claimant as a matter of law does not accept that his case depends on proving that the exogenous factor more than doubles the risk of the index condition.

The Defendant submits that MS is an indivisible disease. It takes the law as set out in Heneghan v Manchester Dry Docks [2016] EWCA Civ 86 at para. 23 about the ways of establishing causation in disease cases. The first category of cases is cases where the claimant is required to prove a ‘but for’ test that the claimant would not have suffered the disease but for the defendant’s negligence. The second category is that where the disease is divisible, the defendant will be liable on the ground that its negligence made a material contribution to the disease: see Bonnington Castings Ltd v Wardlaw [1956] AC 613 (“Bonnington”). The third category is an exception in indivisible injuries called the Fairchild exception applied in mesothelioma or lung cancer cases, where a material increase in the risk of the victim contracting the disease may suffice such as to obviate the need to prove that the external agency did cause or contribute directly to the disease: see Fairchild v Glenhaven Funeral Services Ltd [2002] UKHL 22; [2003] 1 AC 32. The Defendant says that this is not a category 2 case because MS is an indivisible disease. It says that the case is not a category 3 case because that would involve the extension of the Fairchild exception, and there is no reason to do so, and there has been a noted judicial reluctance to extend the same.

The Defendant therefore submits that this case depends on the Claimant establishing that but for the exposure to solvents in his work with the Defendant, he would not have developed MS. It submits that this has two aspects, namely generic causation whether solvent exposure can cause MS, and, if so, individual causation, whether solvent exposure did cause the Claimant’s MS.

Further, the Defendant submits that unless the exposure to the solvents more than doubles the risk of contracting MS, the claim must fail as a matter of law.

The Claimant submits that the law on causation is less clear than that advanced on behalf of the Defendant. In particular, he raises the following issues, namely:

Further and in any event, the Claimant submits that the law in respect of causation is pragmatic and yields to the justice of each case. It draws attention in particular to the following, namely:

The Defendant is critical of the lack of precision of these submissions of the Claimant. It is all very well to say that there are assumptions, but one might look for more tangible attempts to show why they are or may be mistaken. As noted above, Ms Harrison QC submits that MS is a condition which is generally regarded as of unknown aetiology and there is no reason to believe in the light of evidence of the epidemiologists that it would be proven that the exogenous factor in question is capable of causing MS. The need to have a preliminary issue was because, the

Despite this, the Defendant has acknowledged rightly in the context of an application to change experts in which Ms Wilmott of the Government Legal Department said at para. 6 the following:

“Not only is the claim of high value and complexity, and thus of considerable importance to the parties; but it is likely to have a much wider public interest and significance. It has the potential to become a leading precedent on causation in the law and could open the way for other sufferers with MS to argue that their own conditions were ‘caused’ by similar environmental exposures. It is therefore especially important that the trial judge should have the most complete evidence that it is feasible for the parties to provide.”

When pressed about this, Ms Harrison QC recognised entirely properly and realistically that there are areas in this case of a tertiary nature, in other words, capable of going not only to a second court (a first appeal), but even to a third court (a second appeal). To that end, she recognised the scope of the third and fourth points made by the Claimant at paragraph 18 above. She could have added the fifth point too, although the Defendant does not concede that there is scope for serious argument regarding whether the doubling of the risk might not have to be proven in the instant case.

Whilst it is the case of the Defendant that whatever the test to be propounded, the Claimant will be unable to satisfy causation between the exposure to solvents and MS, this is not a case where there has been an application to strike out the claim or for summary judgment. Once it is recognised that the case is going to trial, then it has to be recognised that the points of law as a whole raise real questions. Those issues which might appear not to be particularly convincing must join the mix of points to be explored at trial. That includes whether MS is in fact divisible or indivisible, whether there is to be a broad-brush pragmatic approach to causation and even how the Court is to characterise the psychiatric injury.

In circumstances where this interim application is not going to be dispositive of any part of the claim but is simply case management about the sequence of how to try the issues, it is inappropriate to go into detail about the detailed legal submissions. This is not the occasion on which to have a mini-trial. It is not productive unless the Court could make definitive findings. The areas of law must all be explored at trial. In the interim, assumptions ought not to be made around points of law unless they are settled.

It therefore follows that the points of law are rather less set in stone than they appear in the Defendant’s skeleton argument. As noted, in oral argument, Ms Harrison QC has been entirely fair and helpful to the Court in indicating to the Court possible areas of controversy.

In my judgment, insofar as it is intended to have a preliminary issue based on assumed facts, there are significant problems. They include the following, namely it is arguably wrong to assume that:

It has been assumed thus far that the two trials might last the same time as one long trial. Within the recalling of witnesses and overlapping issues, and the possibility of witnesses contradicting themselves between stage 1 and stage 2 must be the real possibility about the totality of stage 1 and stage 2 being longer than would have been the case if the two stages had been tried at the same time.

There is a more probable event which requires careful consideration, namely the prospect of an appeal against a ruling on stage 1. In view of the evidence of Ms Wilmott, the points of law identified and the realistic recognition of capacity for appeals whichever party might lose a preliminary issue may seek to appeal the case to the Court of Appeal. If the appealing party is the Defendant, then in tune with the application for the preliminary issue, it is likely that there would be resisted stage 2 until the appeal against stage 1 had been concluded. That would then involve a very substantial delay of the case. With the possibility of overlap between stage 1 and stage 2, the complications of that would be greater. The capacity for increases in costs and delays would be increased. If all possibilities are being considered, one also has to take into account that two stages might lead even to two appeals instead of one appeal if all matters were being heard together. By contrast, if stages 1 and 2 are heard at once, then any appeal could follow and include arguments both as regards all liability issues.

An answer of Ms Harrison QC to this concern was the possibility that the trial would be conducted in one go, but with the Court giving judgment on stage 1, and then moving on immediately to stage 2. In discussion, it emerged that this would be predicated on the Court giving its judgment on stage 1 within say a week of the conclusion of the trial of stage 1. I mentioned that that might be expecting too much of the Court. If the law was as difficult as appeared to be the case, it was going to take a good deal of reading of factual material and case law to bring together such a judgment. A period of perhaps a month may be more realistic (and even then, requiring the Judge to have the capacity for substantial writing time). That would be likely to rule out or put in jeopardy a rolling trial.

These problems would not arise if there was one trial. In view of the concession of the Claimant concerning quantum, that could be shelved for later. That would significantly alter the length of the trial. The estimates so far have been 5 days for stage 1 and 7 days for stage 2 (being all of the remaining issues). Ms Harrison QC indicated that stage 2 might last up to 10 days if it is to include quantum. Mr Rawlinson QC estimated that the quantum part might last up to 4 days: Ms Harrison QC did not express a view about that. It is apparent from the foregoing that without quantum, the overall trial on liability issues might be less than 10 days or perhaps up to or just over 10 days. The price for that is in my judgment worth paying. It is to try the related issues of breach of duty, causation and limitation together, and to avoid many of the pitfalls identified in the above paragraphs of this judgment.

There are other problems. They will come to life by considering at this stage the procedural law regarding holding preliminary issues.

That there is a power to direct a trial of a preliminary issue is not controversial. The Claimant draws attention to the following:

A part of the commentary in the White Book at 3.1.10 is as follows:

“In McLoughlin v Grovers (A Firm) [2001] EWCA Civ 1743; [2002] Q.B. 1312 at [66], David Steele J gave the following guidance: (i) only issues which are decisive or potentially decisive should be identified; (ii) the questions should usually be questions of law; (iii) they should be decided on the basis of a schedule of agreed or assumed facts; (iv) they should be triable without significant delay, making full allowance for the implications of a possible appeal; (v) any order should be made by the court following a case management conference.

…

As to (iii) (see above, preliminary issues should be decided on the basis of a schedule of agreed or assumed facts), the first draft of the schedule is often prepared by the claimant and sent to the defendant for agreement or amendment. Before directing a preliminary issue, the court should consider how much effort will be involved in identifying the relevant facts. The greater the effort the less likely it is that the preliminary issue will lead to a saving in costs. If there are serious disputes of fact giving judgment at a trial of the preliminary issue may be unsafe or useless (see generally Steele v Steele [2001] C.P. Rep 106 in which Neuberger J (as he then was) declined to give judgment at a separate trial previously directed by a deputy judge of the High Court).

As to (iv) (see above, triable without significant delay, making full allowance for the implications of a possible appeal) in Re Kenyan Emergency Group Litigation [2016] EWHC 600 (QB) (in which a direction for the trial of preliminary issues was allowed in part only) one of the factors considered was that, in the event of an appeal on one of the preliminary issues sought, the trial of all remaining issues might be delayed by three or four years by which time most of the lay witnesses for both sides (who were very elderly) may not have been capable of giving evidence.”

The law reports are littered with cases where a preliminary issue seemed a good costsaving exercise, but where not sufficient attention was given to the consequences. Remarks like ‘deceptively attractive short-cut’ appear in the reports. In the end, that which is intended to shorten the path sometimes serves considerably to lengthen it. The result is something entirely contrary to the overriding objective despite the best of intentions. None of this means that a trial of a preliminary issue is always a bad idea: it simply has to be approached with caution. None of this means that a trial of a preliminary issue is always a bad idea: it simply has to be approached with caution.

Applying the criteria considered by David Steele J in McLoughlin v Grovers (A Firm) to the instant case and using the numbering therein, the following conclusions arise:

At the hearing the Claimant made submissions by reference to Barrett v Enfield London Borough [2001] 2 AC 550 at 557F-G and Vedanta Resources PLC v Lungowe & ors. [2019] UKSC 20 at para. 48, and with permission of the Court the Defendant has replied by a written note. The Claimant relies on these cases as reminders about the dangers of trying negligence cases on assumed or hypothetical facts. The Defendant submits that neither case provides guidance on the issues of whether to order a preliminary issue or to try causation separately from the other issues. Barrett was a strike-out appeal and Vedanta was an appeal relating to a jurisdictional challenge. The analysis of facts was much less advanced than in the instant case. The cases related to novel and controversial developments in the law of negligence. The Defendant says that any difficulties of law may turn out to be artificial constructs or Micawberism (see Lady Hale at para. 45 in Vedanta). Even if difficult issues of law exist, they will not be fact sensitive. All of that is possible, but in my judgment, absent applications to strike out the claim or for summary judgment which the Defendant properly recognises are inappropriate, it is premature at this stage to make assumptions that the Claimant would lose a preliminary issue or that any points of law would not be fact sensitive. At this stage, it is in my judgment more prudent to resolve the issues in this case on actual rather than assumed or hypothetical facts. In any event, the practical difficulties which would ensue from a decision on assumed facts at stage 1 and possibly a decision on fact finding of different facts at stage 2 as referred to in paragraph 35(1) above should be avoided.

The Defendant has highlighted the judgment of the Court in the case of Saunderson & ors v Sonae Industria (UK) Ltd [2015] EWHC 2264 (QB). It particularly refers to

However confident the Defendant is about the eventual result, this rather puts the cart before the horse. First, there has to be a trial to reach a conclusion as to whether the Claimant’s case fails. That still does not engage Saunderson because that was a case where the Claimant’s conduct of the case was impugned. Absent an application for summary judgment or strike out, which there is not to be, it is premature to make any assumption that either the case will fail, or still further that following such a trial the Claimant’s conduct will be impugned. Fortunately, judicial criticism of the kind quoted in para. 37 above is reserved for an unusual case, and, in that case, it was only at the end of a long and complicated trial. At this interim stage, Saunderson has no application to the instant case.

Having considered all of the matters before the Court, this is not a case where it would be just or prudent to order a trial of a preliminary issue either on the basis of assumed facts or a trial of causation alone without a trial of the other issues as regards liability. It does seem sensible to separate quantum if that can be done easily, but before making such an order, the Court would wish to hear more about how that would work in practice. Further, Ms Harrison QC has not addressed the Court about that issue because it did not arise on her application. At the same time, attention should be given as to whether the medical condition and prognosis of the Claimant is such that his evidence might need to be taken in advance of the trial or in advance of a quantum hearing. As noted above, nothing in this judgment prevents matters from being revisited nearer the trial, but in view of the matters set out above, it is likely that there would need to be a change of circumstances in order to justify trying causation as a preliminary issue in advance of other liability issues.

In the course of argument and, according to the Defendant, in the light of the way that the matter was put at the hearing on behalf of the Claimant, the Defendant accepted that Mr Stear should be asked for his comments on paragraphs 1.4.2 and 1.4.4 only of Professor Cherrie’s “Part 35 Replies” dated 10 February 2021, and whether as a consequence he considered that any change was required in the Joint Report of 2 June 2020. In a subsequent letter of Mr Stear, he stated that he did not disagree with the view of Professor Cherrie on paragraph 1.4.2. and 1.4.4. He still has to consider the papers to which Professor Cherrie refers.

The parties should be given the opportunity to supplement the evidence in the light of this. Since the draft judgment is being sent out within less than 21 days of the hearing, I approve paragraphs 1 and 2 of the draft order sent by the Claimant and in particular that the Claimant may rely upon Professor Cherrie’s report dated 10

There is a disagreement as to costs. The Defendant says that it should have its costs either because the application was unnecessary (on one limb of the Claimant’s submission) or because the Claimant should have made the correction earlier in which case matters could have been agreed with Mr Stear and the application may have been unnecessary. The Claimant says that the costs should be in the case. This is a case where both parties got it wrong in the first place, and where it needed to be corrected.

The Court is unable at this stage to determine which party is correct in these submissions as to costs. It will not be resolved until the further discussions have taken place between the experts, and submissions as to costs revisited in the light of this. This would all be disproportionate and an unnecessary use of the court’s time. In my judgment, the events which have occurred can be viewed as a part of having the experts’ reports before the court in a correct and, if necessary, corrected manner. My preliminary view is that the costs of the application should be costs in the case. I shall reach an ultimate adjudication on costs when the costs of the Defendant’s application are considered.

The parties should draft an order to give effect to the matters set out in this judgment. At the same time, they should seek to agree consequential matters. To the extent that any matters are not agreed, the Court will determine the same.