Shaikh Abdul Rehman & Ors v Secretary of State for Health and Social Care & Ors [2026] EWHC 6 (KB)

[2026] EWHC 6 (KB)

Case No KB-2023-001678 & Ors

IN THE HIGH COURT OF JUSTICE

KING'S BENCH DIVISION

Venue Royal Courts of Justice, Strand, London, WC2A 2LL

Date 12 January 2026

Before

MASTER DAVISON

Between

SHAIKH ABDUL REHMAN & ORSClaimants

SECRETARY OF STATE FOR HEALTH AND SOCIAL CARE & ORSDefendants

Mr Jeremy Hyam KC (instructed by Leigh Day) for Claimants

Mr Robert Dickason (instructed by GLD) for Secretary of State

Mr Alexander Macpherson (instructed by Keoghs) for Keoghs Defendants

Ms Meghann McTague and Ms Lucinda Spearman (instructed by DWF) for DWF Defendants

Mr Tom Collins (instructed by Browne Jacobson) for Abbey Total Care Group

Mr David Roderick (instructed by Bevan Brittan) for Trees Park (Kenyon) Ltd

Mr Sam Holden (of Clyde & Co LLP) for Clyde & Co Defendants

Hearing Hearing date: 17 December 2025

Approved Judgment

This judgment was handed down remotely at 2pm on 12 January 2026 by circulation to the parties or their representatives by e-mail and by release to the National Archives.

.............................

MASTER DAVISON

Introduction and narrative

[1]These applications concern a cohort of 23 claims, all but one of which cite the Secretary of State for Health & Social Care (“the Secretary of State”) as the first defendant and, typically, a care home or the insurer of a care home as the second defendant. The cases make two claims which are:(1) a claim in respect of the contraction of Covid-19 and

(2) a conventional care claim. In all of them the contraction of Covid-19 led to death and the claims are brought under the Law Reform (Miscellaneous Provisions) Act 1934 and/or (where appropriate) the Fatal Accidents Act 1976. The typical claimant is the spouse or child of the deceased. Only a small proportion of the claimants qualify for a bereavement award. Because the deceased was, in each case, an elderly person residing in a care or nursing home, there are no, or no valuable, dependency claims. Hence the claims are typically pleaded at a level below £10,000. Their aggregate value is around £250,000.

[2]In dealing with the applications and with the claims generally I have tried to keep in mind that in each of them a loved one was tragically taken away in the Covid pandemic and that, although the law must put a monetary value on them, the cases are not about money. To the claimants, the discussion of legal principles which follows may seem dry and detached from the very sad underlying events. I express my regret for that and my sympathy for them in their losses.

[3]The deceased all died in the first wave of the pandemic. The claimants contend that the policies issued by the Secretary of State on 19 March 2020 and 2 April 2020 (“the March Discharge Requirements” and “the April Admissions Guidance”), which did not require asymptomatic admissions to care / nursing homes to be isolated for 14 days so far as practicable, caused the deceased to contract Covid-19. As against the care homes, the claimants contend that the Covid-19 protection measures taken by the defendants were inadequate and/or not properly implemented or observed. Additionally, against the care homes, the claimants make more conventional allegations of shortcomings in care. This judgment is not concerned with this latter aspect of the claims.

[4]The Secretary of State was first notified of the claims on 3 November 2022. There was a limitation moratorium to allow further investigations by the claimants’ team at Leigh Day (who have acted throughout) and for compliance thereafter with the Pre Action Protocol. The claimants were invited to set out their case on causation, specifically how “but for the allegations of breach of duty relied upon Covid-19 infection and death would have been avoided”. On 29 November 2023, the claimants served draft Particulars of Claim. These pleaded a causation case based exclusively on the “material increase in risk” principle which derives from the well-known case of Fairchild v Glenhaven Funeral Services Ltd

[2003] 1 AC 32

[2002] UKHL 22

. On 22 December 2023 further draft Particulars of Claim were served, this time adding a case on causation based on “material contribution to injury”. This principle derives from the equally well-known case of Bonnington Castings v Wardlaw

[1956] AC 613

. The Secretary of State responded on 1 May 2024. I quote from the first page of this 23 page letter:

“It is further denied that the policy failures alleged were causative of the deaths of your clients’ relatives, particularly in circumstances where (a) Covid-19 was ubiquitous nationwide and everyone, whether resident in care and nursing homes or otherwise, faced a significant risk of infection; (b) your clients accept that they cannot identify the source of their relatives’ infections; and (c) it is at the same time alleged against the care providers concerned that they failed to follow the Covid-19 guidance that was in place. We do not consider that your clients are able to prove causation against the SSHSC in such circumstances, either on the Fairchild basis initially relied upon, or upon the new basis of a material contribution to infection.”

[5]The section of the letter quoted captures the dilemma facing these claimants and, indeed, any claimant bringing a claim based on the contraction of a disease where there are multiple exposures and multiple sources of the agent causing the disease, some “innocent” and some not.

[6]Finalised Particulars of Claim were served and filed on or around 7 March 2025 and Defences were served and filed on or around 6 June 2025. On 29 July 2025, the Secretary of State applied to strike out the claims based upon the contraction of Covid-19, or for reverse summary judgment on these claims. The nursing / care home defendants (save for the Clyde & Co defendants, who have remained neutral) have followed suit. The defendants say that resort to the Fairchild and Bonnington Castings principles is impermissible and doomed to failure and that the “no reasonable grounds” and/or “no real prospect” tests set out CPR r. 3.4(2)(a) and r. 24.3 are made out. The claimants say that they have reasonable prospects of success on both principles. The claimants’ case on causation

[7]The relevant paragraphs of the Particulars of Claim, as served, state as follows, (I have taken the Rehman claim as an example):

“88. Mrs Rehman, whose date of birth was 17 February 1945, suffered the following injuries as a consequence of the First and Second Defendants’ negligence and in the latter case breaches of human rights. 89. Further, the First and Second Defendants’ negligence and/ or breach of Article 2 ECHR (in the latter case) materially increased the risk of Mrs Rehman contracting Covid-19, which caused death and/ or more than minimally, trivially or negligibly contributed to the same. The Claimant relies upon the principles in Bonnington Castings Ltd v Wardlaw [1956] 1 AC 613 and Holmes v Poeton Holdings Ltd [2023] EWCA Civ 1337. 90. The Claimant contends that the conditions specified in Fairchild v Glenhaven Funeral Services Ltd [2003] 1 AC 32, as explained and modified in later jurisprudence including Sanderson v Hull [2009] CP Rep 12, apply to the circumstances of this case. 91. In particular, the failure of the First Defendant to advise that when asymptomatic hospital patients (other than those who had tested negative) and asymptomatic individuals previously living in the community (other than those who had tested negative) were admitted to a care / nursing home, they should, so far as practicable, be kept apart from other residents for 14 days, materially contributed to and in the alternative materially increased the risk of Mrs Rehman contracting Covid-19, which caused death. Asymptomatic but Covid-19 positive admissions to care/nursing homes were transmitting Covid-19, materially contributing to the quantity of Covid-19 viral particles present in care/ nursing homes, and it is scientifically impossible to identify all individuals transmitting at the time and who transmitted Covid-19 to Mrs Rehman.”

[8]In addition to the above, Mr Hyam KC’s skeleton argument, at paragraphs 6 and 7 says as follows: “6. It is simply not possible for science to say which particle or group of particles circulating in the environment in the care homes where the deceased were resident in the period March to April 2020 caused Covid-19 infection in any of the Claimant cases. Nor is it possible to say (from a scientific point of view) in relation to any particular patient that ‘on the balance of probabilities’ the Covid-19 infection was caused by, for example, the discharge of an asymptomatic or presymptomatic patient from hospital to a care home. 7. The precise degree to which the discharge of asymptomatic and presymptomatic hospital patients to care homes (or the admission of asymptomatic and presymptomatic community patients to care homes without isolation) increased the risk of Covid-19 infection to care home residents during the period March to April 2020 will also probably never be known. This is because there is no reliable way of counting the particles by way of background-levels in care homes, nor any way of knowing whether it was the particular particles introduced by, for example, discharges from hospital or admissions from the community of presymptomatic and asymptomatic patients, which were the cause of the infection in any particular case. But there is clear and (what is understood to be) undisputed evidence emanating from the First Defendant that broader statements as to material increase in risk and contribution to cause can be made.” [The skeleton continues with extensive quotations from publications in the public domain.]

[9]In his oral submissions, Mr Hyam KC added that because there was no testing at the material time, this too made proof of causation scientifically impossible. The submissions of the parties

[10]Mr Hyam KC for the claimants took me carefully through the material quoted in his skeleton argument and which was exhibited to the witness statement of Emma Jones of Leigh Day dated 3 December 2025. The material included: i. The DHSC’s Consensus statement on the association between the discharge of patients from hospitals and Covid in care homes. ii. Public Health England’s publication: A data linkage approach to assessing the contribution of hospital-associated SARS-Cov-2 infection to care home outbreaks in England. iii. Extracts from the evidence of Professor Beggs to the UK Covid-19 Inquiry. iv. An undated letter from Dr MA Zuckerman, a consultant virologist and Honorary Reader at King’s College Hospital.

[11]In summary, the material was submitted to support at least the following propositions.

[12]It was highly likely that some care home outbreaks were caused by discharges from hospital – particularly in the early months of the pandemic. Much infection was transmitted by persons who were asymptomatic or presymptomatic. The risk of acquiring a Covid-19 infection was proportional to the number of respiratory aerosol particles inhaled and was therefore dose related. As to dose:

“… it has been estimated that the expected infectious dose for SARS-CoV-2 in humans is thought to be approximately in the range 300 to 2000 virus particles with an average (median value) being about 600 virus particles (Prentiss et al 2022).”

[13]The mechanism of injury was as follows:

“… chance contributes greatly to whether or not an individual exposed to an infectious aerosol will contract an infection. For a SARS-CoV-2 infection to occur the following events must happen: (i) the inhaled respiratory aerosol must contain the virus; (ii) the aerosol particles that come into contact with the ACE2 receptors must contain viruses; (iii) the virus particles in the aerosol must be fit enough to bind to the ACE2 receptors and enter the host's cell; and (iv) once inside the cell, the virus must overcome the host's immune defences and be able to replicate. If the process fails at any of these stages, infection cannot occur. Consequently, because many virus particles will either miss the target ACE2 receptors, fail to bind because they are damaged, or be overcome by the host's immune system, it means that generally a large number of virus particles need to be inhaled (i.e., the expected infectious dose) in order for a few to establish an infection (Prentiss et al 2022).”

[14]Mr Hyam KC acknowledged that the generic Particulars of Claim did not, in the great majority of cases, plead that there was in fact a tortious increase in circulating viral particles due to the discharge, without a 14 day isolation, of a patient from hospital to a care home. This was because the claims had not reached the disclosure stage and this information was not yet available to the claimants. But he gave an example of one case where there was information available. This was the case of Weager KB-2023-002041. The Particulars of Claim in that case pleaded that there had been the admission of a resident to the home from hospital; the resident was (it is inferred) asymptomatic but infectious. He or she had not been isolated “until after the resident had moved to areas of the home which were not the resident’s bedroom”. Mr Hyam KC said that after disclosure he expected to be able to plead to the like effect in the remainder of the claims. He also relied upon a concession made by Mr Dickason for the Secretary of State to the effect that further evidence, such as that which was available to the claimant in the Weager case, might become available in some or all of the other cases. He (Mr Hyam KC) invited me to consider his submissions on this basis.

[15]As to material contribution, Mr Hyam KC accepted and averred that Covid-19 was an indivisible disease. But the Bonnington Castings principle applied to indivisible disease as it did to divisible disease; see e.g. Holmes v Poeton Holdings Ltd

[2024] KB 521

[2023] EWCA Civ 1377

at paragraph 60. It was reasonably arguable that Covid-19 was a cumulatively caused disease in the sense that it was dose related. Here, although there were, or may have been, multiple potentially infective viral particles circulating in the air of the relevant nursing home – some “innocent” and some “guilty” – it would be open to the court to find that the “guilty” particles made a material contribution to what Mr Hyam KC called “the mechanism of injury”. This was because the contraction of Covid-19 was dose related and the guilty particles increased the dose.

[16]As to material increase in risk, Mr Hyam KC submitted that the categories of case that would fall within what has come to be called the Fairchild enclave were not confined to mesothelioma. It was, indeed, expressly acknowledged in Fairchild and in Sanderson v Hull [2009] PIQR P7

[2008] EWCA Civ 1211

that other diseases and conditions might qualify. Here, he submitted that the conditions propounded by Lord Rodger in Fairchild were all made out and that it was at least reasonably arguable that the claimants could succeed on this basis.

[17]Mr Hyam KC reminded me of the well-known principles applicable to strike-out and summary judgment applications, in particular those that were engaged “in an area of developing jurisprudence”: “It is not appropriate to strike out a claim in an area of developing jurisprudence, since, in such areas, decisions as to novel points of law should be based on actual findings of fact (Farah v British Airways, The Times, 26 January 2000, CA referring to Barrett v Enfield BC [2001] 2 A.C. 550; [1989] 3 W.L.R. 79, HL). A statement of case is not suitable for striking out if it raises a serious live issue of fact which can only be properly determined by hearing oral evidence (Bridgeman v McAlpine-Brown, 19 January 2000, unrep., CA). An application to strike out should not be granted unless the court is certain that the claim is bound to fail (Hughes v Colin Richards & Co

[2004] EWCA Civ 266

; [2004] P.N.L.R. 35, CA (relevant area of law subject to some uncertainty and developing, and it was highly desirable that the facts should be found so that any further development of the law should be on the basis of actual and not hypothetical facts)).” (White Book, Vol 1 at 3.4.2)

[18]I will not recite the submissions of the defendants. I have substantially accepted their submissions and the content of them will be apparent from what follows. Discussion and conclusions Material contribution

[19]A helpful starting point for a discussion of the issues that arise in this case can be found in the speech of Lord Phillips in Sinkiewicz v Greif (UK) Ltd

[2011] 2 AC 229

[2011] UKSC 10

. At paragraphs 12 – 17 he set out an overview of the principles of causation in relation to disease:

“12. Many diseases are caused by the invasion of the body by an outside agent. Some diseases are caused by a single agent. Thus, malaria results from a single mosquito bite. The extent of the risk of getting malaria will depend upon the quantity of malarial mosquitoes to which the individual is exposed, but this factor will not affect the manner in which the disease is contracted nor the severity of the disease once it is contracted. The disease has a single, uniform, trigger and is indivisible. 13. The contraction of other diseases can be dose related. Ingestion of the agent that causes the disease operates cumulatively so that, after a threshold is passed, it causes the onset of the disease. Lung cancer caused by smoking is an example of such a disease, where the disease itself is indivisible. The severity of the disease, once it has been initiated, is not related to the degree of exposure to cigarette smoke. 14. More commonly, diseases where the contraction is dose related are divisible. The agent ingested operates cumulatively first to cause the disease and then to progress the disease. Thus, the severity of the disease is related to the quantity of the agent that is ingested. Asbestosis and silicosis are examples of such diseases, as are the conditions of vibration white finger and industrial deafness, although the insults to the body that cause these conditions are not noxious agents. For this reason it is important to distinguish between asbestosis and mesothelioma when considering principles of causation. 15. Mesothelioma is an indivisible disease. As I shall explain there is uncertainty as to whether its contraction is related to the amount of asbestos fibres ingested. 16. It is a basic principle of the law of tort that the claimant will only have a cause of action if he can prove, on balance of probabilities, that the defendant's tortious conduct caused the damage in respect of which compensation is claimed. He must show that, but for the defendant's tortious conduct he would not have suffered the damage. This broad test of balance of probabilities means that in some cases a defendant will be held liable for damage which he did not, in fact, cause. Equally there will be cases where the defendant escapes liability, notwithstanding that he has caused the damage, because the claimant is unable to discharge the burden of proving causation. 17. There is an important exception to the “but for” test. Where disease is caused by the cumulative effect of the inhalation of dust, part of which is attributable to breach of duty on the part of the defendant and part of which involves no breach of duty, the defendant will be liable on the ground that his breach of duty has made a material contribution to the disease — Bonnington Castings Ltd v Wardlaw [1956] AC 613. The disease in that case was pneumoconiosis. That disease is divisible. The severity of the disease depends upon the quantity of silica inhaled. The defendant did not, however, argue that, if held liable, this should only be to the extent that the dust for which it was responsible had contributed to the plaintiff's symptoms. It was held liable for 100% of the disease. There have, however, been a series of cases at first instance and in the Court of Appeal in which it has been recognised that where there has been a number of exposures of a claimant to bodily insults that have cumulatively caused a divisible disease, responsibility should be apportioned so that an individual defendant is liable for no more than his share of the disease. This apportionment may necessarily be a rough and ready exercise: see Mustill J's analysis in Thompson v Smiths Shiprepairers (North Shields) Ltd [1984] QB 405 at pp 437–444 and the cases cited in McGregor on Damages, 18th ed (2010) at 8–010 to 8–016.”

[20]As is clear from this passage, the basic rule in a disease case is that the claimant must prove that the defendant’s tortious conduct caused the disease in respect of which compensation is claimed. There is no doubt that this ordinarily applies to infectious diseases, including Covid-19. For the claimants in these claims to take advantage of the modified principle set out in Bonnington Castings Ltd v Wardlaw

[1956] AC 613

they must show that the deceased’s Covid-19 was “caused by the cumulative effect of the inhalation of [viral particles] part of which is attributable to breach of duty on the part of the defendant and part of which involves no breach of duty”; see paragraph 17 of the passage from Sienkiewicz quoted above. In such a case, the defendants might be held liable on the ground that their breach of duty “made a material contribution to the disease”.

[21]Bonnington Castings was a case where the claimant had contracted pneumoconiosis from exposure to silica dust in his employer’s foundry. Some of the dust came from the swing grinders and some from the pneumatic hammer. That from the hammer could not have been prevented and so was “innocent” dust. That from the swing grinders was preventable. But the dust extraction plant was not kept free from obstruction. It was frequently choked and ineffective. This was a breach of duty and therefore the dust from the swing grinders was “guilty” dust. The court inferred from the evidence that the “guilty” dust made at least a substantial contribution to the claimant’s disease. Lord Reid said that the swing grinders “did in fact contribute a quota of silica dust which was not negligible to the pursuer’s lungs and therefore did help to produce the disease”; see at p. 623.

[22]I was referred to other cases including(a) Holmes (see above) where the Court of Appeal affirmed that the Bonnington Castings principle was capable of applying to a case where exposure to the chemical TCE was said to have made a material contribution to the development of the claimant’s Parkinson’s disease (an indivisible injury);

(b) Bailey v MOD

[2009] 1 WLR 1052

[2008] EWCA Civ 883

where the Court of Appeal approved Foskett J’s application of the principle to a case where the claimant’s cardiac arrest was caused by (i) an actionable lack of care and (ii) non-actionable pancreatitis and “medical science could not establish the probability that but for a particular act of negligence the injury would not have occurred, but could establish that the contribution of the negligent cause was material or something more than negligible”;

[2016] AC 888

[2016] UKPC 4

, a clinical negligence case where the Privy Council confirmed that it was immaterial to the application of the Bonnington Castings principle whether the cumulative factors operated concurrently or successively.

[23]In my view, it is very clear that the Bonnington Castings principle does not assist the claimants in this case.

[24]I will assume in the claimants’ favour that Covid-19 is a cumulative condition in the sense put forward by them which was that it is, or may be, caused by the cumulative effect of infective particles acting cumulatively on the body and it requires a threshold dose of viral particles to be inhaled or ingested before infection is likely to occur such that multiple sources of Covid-19 viral particles can cause infection acting cumulatively. (I take this definition from question 2 of the three questions put to Dr Zuckerman, the claimants’ expert virologist. He answered it in the affirmative, (though the defendants were highly critical of his reasoning).)

[25]However, the fundamental problem facing these claimants is the concessions they have made – principally in paragraphs 6 & 7 of Mr Hyam KC’s skeleton argument cited at paragraph 8 above. The claimants may, as the defendants accepted, show that the deceased were exposed to “guilty” viral particles attributable to breach of duty on the part of the defendants. They may also show that the presence of “guilty” particles increased the risk of them developing Covid-19 by increasing the available dose. But what they have stated in the clearest possible terms is that they cannot prove that it was “guilty” viral particles which actually caused / partly caused their disease. There is no doubt that this is what they are required to do. Mr Hyam KC characterised the role of the guilty particles as contributing to the “mechanism of injury”. This form of words is slightly misleading. “Mechanism of injury” refers to the way that an injury is inflicted. It is distinct from the injury itself. In these cases, the mechanism of injury is actual infection by “guilty” Covid-19 viral particles. It is not an increase in circulating virus or a corresponding increase in the risk or probability of infection. But actual infection by “guilty” particles is the very thing which the claimants have accepted they cannot show.

[26]This case is different from the cases relied upon by the claimants. In Bonnington the claimant was shown to have inhaled dust all of which produced his disease. The “guilty” dust therefore did materially contribute. In Williams all the culpable delay was found to have materially contributed to the sepsis. In Bailey the culpable lack of care was found to have materially contributed to the claimant’s fragility, which in turn led to her cardiac arrest. None of these cases was decided on the basis of an increased risk or probability of injury. They were decided on the basis of actual contribution to injury.

[27]If the claimants’ argument as to the applicability of Bonnington Castings was correct it would have profound implications. To show a culpable increase in the environment of a circulating virus (or any other agent of disease) and a corresponding increase in the risk of disease is not the same as showing that that agent caused or partly caused or (to adopt Lord Reid’s expression) “helped to produce” the disease. Such a principle would “open the floodgates”. It would, as Mr Macpherson pointed out, bring the generality of disease cases within the Fairchild principle, but without the Fairchild control mechanisms.

[28]As an afterword on this topic I should mention that when, during Mr Hyam KC’s submissions, I questioned whether he was conflating material contribution to injury and material increase in risk, he drew my attention to a passage from Lord Reid’s speech in McGhee v NCB

[1973] 1 WLR 1

where Lord Reid said that “from a broad and practical viewpoint” he could see “no substantial difference between saying that what the defender did materially increased the risk of injury to the pursuer and saying that what the defender did made a material contribution to his injury”; see at page 5B. But this passage does not help the claimants because, as has now come to be widely recognised, McGhee was an “avant la lettre” application of the Fairchild exception; see Lord Hoffmann’s judgment in Barker v Corus UK Ltd

[2006] 2 AC 572

[2006] UKHL 20

at paragraph 13. Mr Hyam KC’s reference to Lord Reid’s remarks in McGhee was in fact an illustration or vindication of the argument against him. The argument was that his appeal to the Bonnington Castings principle was, in reality, just the Fairchild principle dressed up differently. That is, in my view, a fair characterisation. Material increase in risk

[29]In mesothelioma claims, the Fairchild principle relaxes the normal rules of causation so as to cater for the scientific impossibility of proving which asbestos fibres or which exposure actually caused the victim’s disease. The claimant in such a case is required to prove only that the exposure was such as to create a "material increase in risk" of contracting mesothelioma.

[30]It is now settled that in order for a claimant to bring themselves within the Fairchild enclave, they must satisfy the requirements laid down by Lord Rodger in Fairchild, as modified in Barker v Corus Ltd

[2006] UKHL 20

. These were brought together by Janet Smith LJ in the case of Sanderson v Hull [2009] PIQR P114

[2008] EWCA Civ 1211

at paragraphs 47 & 48: “47. Finally, Lord Rodger of Earlsferry adopted Lord Hutton's analysis but also sought to set out the conditions which would be necessary before an inference of causation should be drawn. At paragraph 170, he said: "First, the principle is designed to resolve the difficulty that arises where it is inherently impossible for the claimant to prove exactly how his injury was caused. It applies, therefore, where the claimant has proved all that he possibly can, but the causal link could only ever be established by scientific investigation and the current state of the relevant science leaves it uncertain exactly how the injury was caused and, so, who caused it. McGhee and the present cases are examples. Secondly, part of the underlying rationale of the principle is that the defendant's wrongdoing has materially increased the risk that the claimant will suffer injury. It is therefore essential not just that the defendant's conduct created a material risk of injury to a class of persons but that it actually created a material risk of injury to the claimant himself. Thirdly, it follows that the defendant's conduct must have been capable of causing the claimant's injury. Fourthly, the claimant must prove that his injury was caused by the eventuation of the kind of risk created by the defendant's wrongdoing. In McGhee, for instance, the risk created by the defendant's failure was that the pursuer would develop dermatitis due to brick dust on his skin and he proved that he developed dermatitis due to brick dust on his skin. By contrast, the principle does not apply where the claimant has merely proved that his injury could have been caused by a number of different events, only one of which is the eventuation of the risk created by the defendant's wrongful act or omission. Wilsher is an example. Fifthly, this will usually mean that the claimant must prove that his injury was caused, if not by exactly the same agency as was involved in the defendant's wrongdoing, at least by an agency that operated in substantially the same way. A possible example would be where a workman suffered injury from exposure to dusts coming from two sources, the dusts being particular of different substances each of which however could have caused his injury in the same way. Sixthly, the principle applies where the other possible source of the claimant's injury is a similar, but lawful, act or omission of the same defendant. I reserve my opinion as to whether the principle applies where the other possible source of injury is a similar but lawful act or omission of someone else or a natural occurrence." 48. In Barker, at paragraph 97, Lord Rodger accepted that his sixth condition had been too narrowly formulated and held that the principle did apply where the other possible source of injury is a similar but lawful act or omission of the defendant or of someone else or a natural occurrence. Lord Hoffmann was of the same view. At paragraph 17, Lord Hoffmann said: "It should not therefore matter whether the person who caused the non-tortious exposure happened also to have caused a tortious exposure. The purpose of the Fairchild exception is to provide a cause of action against a defendant who has materially increased the risk that the claimant will suffer damage and may have caused that damage but cannot be proved to have done so because it is impossible to show, on a balance of probability, that some other exposure to the same risk may not have caused it instead. For this purpose it should be irrelevant whether the other exposure was tortious or non-tortious, by natural causes or human agency or by the claimant himself." Thus, both Lord Hoffmann and Lord Rodger were agreed that Lord Rodger's sixth condition had not been correctly stated in Fairchild. Indeed it seems to me that it has disappeared. It is necessary to identify the 'other exposure' which might have been the cause of the injury but it does not matter whether that other exposure was tortious or who was responsible for it.” "First, the principle is designed to resolve the difficulty that arises where it is inherently impossible for the claimant to prove exactly how his injury was caused. It applies, therefore, where the claimant has proved all that he possibly can, but the causal link could only ever be established by scientific investigation and the current state of the relevant science leaves it uncertain exactly how the injury was caused and, so, who caused it. McGhee and the present cases are examples. Secondly, part of the underlying rationale of the principle is that the defendant's wrongdoing has materially increased the risk that the claimant will suffer injury. It is therefore essential not just that the defendant's conduct created a material risk of injury to a class of persons but that it actually created a material risk of injury to the claimant himself. Thirdly, it follows that the defendant's conduct must have been capable of causing the claimant's injury. Fourthly, the claimant must prove that his injury was caused by the eventuation of the kind of risk created by the defendant's wrongdoing. In McGhee, for instance, the risk created by the defendant's failure was that the pursuer would develop dermatitis due to brick dust on his skin and he proved that he developed dermatitis due to brick dust on his skin. By contrast, the principle does not apply where the claimant has merely proved that his injury could have been caused by a number of different events, only one of which is the eventuation of the risk created by the defendant's wrongful act or omission. Wilsher is an example. Fifthly, this will usually mean that the claimant must prove that his injury was caused, if not by exactly the same agency as was involved in the defendant's wrongdoing, at least by an agency that operated in substantially the same way. A possible example would be where a workman suffered injury from exposure to dusts coming from two sources, the dusts being particular of different substances each of which however could have caused his injury in the same way. Sixthly, the principle applies where the other possible source of the claimant's injury is a similar, but lawful, act or omission of the same defendant. I reserve my opinion as to whether the principle applies where the other possible source of injury is a similar but lawful act or omission of someone else or a natural occurrence." "It should not therefore matter whether the person who caused the non-tortious exposure happened also to have caused a tortious exposure. The purpose of the Fairchild exception is to provide a cause of action against a defendant who has materially increased the risk that the claimant will suffer damage and may have caused that damage but cannot be proved to have done so because it is impossible to show, on a balance of probability, that some other exposure to the same risk may not have caused it instead. For this purpose it should be irrelevant whether the other exposure was tortious or non-tortious, by natural causes or human agency or by the claimant himself."

[31]Since Fairchild there have been attempts to apply the principle beyond the field of mesothelioma claims. Although the principle is capable of general application, those attempts have been almost uniformly unsuccessful. Further, as the defendants in this case were quick to point out,(a) there are many judicial pronouncements which emphasise the exceptionality of the Fairchild principle and the desirability of strict adherence to its narrow parameters and

(b) one of the unsuccessful attempts was a Covid-19 case. This case was a county court case, upheld (on this point) on appeal to the High Court: see Edwards v 2 Sisters Food Group Ltd

[2024] EWCC 21

and

[2025] EWHC 1312 (KB)

[32]The claimants in that case worked “shoulder to shoulder” in a food processing factory. By reason, they alleged, of inadequate Covid-19 precautions, they contracted the disease. They relied on the very large number who caught Covid over a very short period. At least one (and perhaps more) could say that because they lived alone, travelled alone and had not gone out at all, other exposures were minimal or non-existent. It is important to note that – as would be normal – the claimants were seeking to prove causation on ordinary principles. Fairchild was a fallback submission. The county court judge (Her Honour Judge Owen) gave summary judgment in favour of the defendant. That decision was reversed by Sir Peter Lane on appeal – essentially because he found that the claimants had a reasonably arguable case on ordinary “but for” principles. The claimants’ alternative case based on Fairchild therefore did not arise for decision. HHJ Owen had found that that alternative case would have required “an exception” to Fairchild because (if I understand her judgment correctly) Covid-19 was “everywhere, not just in the chicken processing plant” and this was a virus “over which an employer would not be able to exercise control in the way an employer would be able to prevent someone developing mesothelioma by ensuring that they did not come into contact with asbestos”. Although it was obiter, Sir Peter Lane, agreed with this reasoning because he too said that for the claim to succeed on a Fairchild basis would require “a new exception”. It is apparent that Sir Peter Lane gave only the briefest consideration to this point. With the greatest respect to both judges, it seems to me that there are in fact considerable difficulties with the reasoning of HHJ Owen, albeit that I agree with the outcome. It was immaterial that the other source of exposure was non-tortious; see paragraph 48 of the judgment of Janet Smith LJ in Sanderson v Hull quoted above. It was also immaterial that the employer had no control over other exposures. That would always be the case. If Judge Owen meant that the employer had no control over the spread of the Covid-19 virus in its factory, then that was a conclusion that was not open to her on a summary judgment application – as Sir Peter Lane found. It was also a conclusion about breach of duty, not causation. The question in Edwards was not, as it seems to me, whether the application of Fairchild to a case of viral infection required an exception, it was whether that kind of case fell within the Fairchild enclave at all.

[33]In my view, these cases very clearly do not fall within the enclave and the claimants have no reasonable grounds / no real prospect of showing that they do.

[34]The problem is that the claimants cannot show that it is “inherently impossible” for them to prove how their injury was caused. This is the first of the conditions put forward by Lord Rodger. The words “inherently impossible” mean that this is a condition to be applied ab initio to a class of claims that qualify. It is not to be applied to claims which fall to be decided on ordinary causation principles but which have run into difficulties of proof. To put that differently, the Fairchild principle is not an alternative or a fallback. Although it can be said that these claimants have from the outset pleaded their claims as Fairchild claims, it is still a fallback position for them in the sense that (as was accepted in argument) they are driven to do so because of difficulties of proof that arise in their particular claims – not in Covid-19 claims more generally. That Covid-19 claims, like other infectious disease claims, can be proved in the ordinary way is illustrated by the Edwards case and by many others that have come before the courts. Of course, infectious disease cases can present formidable evidential problems. In Edwards there were the confounding factors identified by the judge, the chief of which was exactly the same as confronts these claimants. The Covid-19 virus was very widespread and the claimants could have picked it up via a non-tortious route. It appears that the Edwards claimants planned to address that difficulty by reliance on the surge in infections within a very short space of time, by pointing to a likely, tortious route of infection and by excluding or minimising other sources. These claimants might have approached their claims in broadly the same way. Their claims are not in the same category as mesothelioma claims. The difference lies in the inherent scientific impossibility of attribution to a particular point in time and particular causative fibres in a mesothelioma case. To utilise a theoretical example given by Mr Macpherson in his oral submissions, a claimant in a mesothelioma claim whose entire working life had been captured on CCTV and whose working conditions had been scientifically monitored and documented throughout would be no better off in terms of proof of causation than a mesothelioma claimant who could deploy no such evidence. The contrast with these claimants is obvious. Their difficulty is not, in truth, scientific impossibility; it is lack of evidence.

[35]I do not think that it is unjust to require Covid-19 claims to be proved in the ordinary way and on ordinary “but for” principles. If the claims were permitted to go forward on a Fairchild basis it would mean that the claimants would need to do no more in each case than show a non-negligible increase in circulating viral particles attributable to a tortious act or omission. As Mr Dickason pointed out in his oral submissions, an infected (but perhaps asymptomatic or presymptomatic) healthcare worker omitting to wear a mask for a day might, without more, be held responsible for all ensuing Covid infections throughout the care home. If the policies contained in the March Discharge Requirements and the April Admissions Guidance were held to be tortious then the Secretary of State might be found liable on a very large scale without it being shown that those policies had actually caused any given infection or death. In both scenarios the outcome is disproportionate and manifestly unfair to the defendants.

[36]For these reasons, the Covid-19 element of the claims must be struck out and/or summary judgment must be given in favour of the defendants on this aspect. In so deciding I have not overlooked Mr Hyam KC’s appeal to the principles cited in the passage from the White Book to which he drew my attention. I am very familiar with those, and also with the principle that a strike out / summary judgment application is not the occasion for a “mini trial”. But no such principles are transgressed by my decision. This is not an area of uncertain or developing jurisprudence. The contrary is the case. The Bonnington Castings principle and the Fairchild principle derive from House of Lords and Supreme Court decisions and can now be regarded as settled law. Nor have I embarked on a mini trial. Rather, I have applied those principles to a case on causation pleaded in wholly unequivocal terms. In this, as in any, strike out or summary judgment application, regard must also be had to the unnecessary cost and delay (including to the claimants) that would be produced by failing to grasp the nettle and terminate claims that are sure to fail. Despite my sympathy for the claimants, these claims fall into that category.

[37]I invite counsel to submit an order reflecting the above.