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Loss of a Chance Law in England and Wales Leaves Much to be Desired for Claimants

*** Disclaimer *** I am not a lawyer. I am an undergraduate law student publishing my writing out of interest for anyone who might like to read it. The following essay was submitted as part of a final assessment and received a 2:1.


Sir John Donaldson M.R. said in Hotson v East Berkshire [1987] AC 750 said, ‘As a matter of common sense, it is unjust that there should be no liability for failure to treat a patient, simply because the chances of a successful cure by that treatment were less than 50 per cent.’ This essay will discuss the case law on loss of a chance and examine its impact on claimants. In particular, I will argue that loss of a chance in English tort law is too restrictive for claimants, particularly in cases involving professional negligence. I will first consider the differences between claiming loss of a chance under contract law versus tort law. I will go on to explain that allowing claims for loss of a chance in tort law would provide much-needed legal certainty while bridging the gap between contract and tort law, allowing generally for a more uniform law of obligations. Additionally, in cases involving professional negligence, I will argue that a contract often exists between a claimant and defendant and therefore it logically follows that tort law ought to follow contract law allowing claimants to recover damages in such cases where the defendant has been found to be negligent and where this negligence resulted in loss of a chance. This will be distinguished from cases where no argument could be made that a contract exists between the parties, such as claims in negligence between road users, where the parties were unknown to each other prior to the incident resulting in the claim.

Secondly, I will consider cases of medical negligence, solicitor’s negligence and highlight the flaws of the all-or-nothing approach within the balance of probabilities. In particular, I will focus on Lord Briggs’ judgment in Perry v Raleys Solicitors [2019] UKSC 5. In this judgment, Lord Briggs discusses problems which result from the balance of probabilities and this all-or-nothing approach, and the impact of this approach on claimants.

Finally, I will consider the floodgates argument that allowing claimants to recover for loss of a chance in tort law specifically in cases of professional negligence would overwhelm the courts. I will go on to explain how allowing claims for loss of a chance in professional negligence would not open the floodgates and will focus particularly on the non-negligible loss of chance (loss of at least a 10% chance).

Bridging the Gap: Unifying Contract and Tort Law

Croom-Johnson L.J. said in obiter of Hotson v East Berkshire Health Authority[1], ‘There is nothing in the proposed distinction between contract and tort. There would be no sense in a distinction which allowed damages to be recovered from a private doctor but not against a National Health Service doctor.’ Lord Croom-Johnson goes on to explain that it is not sufficient to be a ‘figure in a statistic’, but that claimants ought to be able to recover damages if they can prove they would be in the percentage bracket who would have made a recovery but for the negligence of the defendant. This statement can be used to explain the differences in approach between contract and tort law. In situations involving private doctors, the patient would pay the doctor for their services, establishing a contractual relationship and providing consideration to form the contract. However, in situations involving doctors from the National Health Service, no consideration passes directly from the patient to the doctor and therefore one of the requirements for forming a contract is not present. The statement by Croom-Johnson L.J. discussing this distinction is relevant here. It would not be logical, all things being equal, that a patient could recover damages for loss of a chance from a private doctor but not from a National Health Service doctor. It would logically follow, then, that a claimant in either situation should be able to recover. If both doctors are negligent, and this negligence results in a significant loss of a chance for recovery (discussed below), then there should be no distinction in liability between the publicly or privately funded doctor.

This is distinguished from Mrs. Justice Obi’s explanation of the loss of a chance doctrine in Kingsley Napley LLP v Harris[2] in which she explains (in a case related to a solicitor’s negligence), ‘…the court must determine whether there would have been a real and substantial chance… of the claimant being better off as he alleges if he had acted differently. In practice this means that an evaluation will be carried out where the value of the chance is between about 10% and 90%’. If we apply this analogy which Mrs. Justice Obi derived from the Court of Appeal[3] and Supreme Court[4] to Hotson v East Berkshire[5], then the claimant’s 25% loss of a chance for recovery would have been significant enough to have been awarded damages, although likely discounted 75% from the full amount.

To provide an example in contract law, it was found by the Supreme Court in Morris-Garner v One Step (Support) Ltd[6] that a claimant could be awarded damages for loss of a chance to negotiate a payment for allowing the defendant to perform a behaviour which was a breach of the contract. This is a case which highlights the difference between contract and tort, where loss of a chance can be claimed in the former but not in the latter.

All-or-Nothing: The Balance of Probabilities Leaves No Room for a Flexible Approach

Another issue with recovering damages in tort law under the balance of probabilities is the all-or-nothing approach. As noted by Lord Reid in Davies v Taylor[7], there is a negligible difference ‘between a probability of 51 per cent and a probability of 49 per cent.’ However, on the balance of probabilities, a claim with 51% probability will succeed and be awarded 100% of the damages, while a claim at 49% probability will fail and receive no damages. The absurdity of these particular circumstances is noted by Lord Briggs in Perry v Raleys Solicitors[8]. In fact, Lord Briggs goes on to note that courts will sometimes depart from this all-or-nothing approach in cases where such an approach would be absurd, and also because such cases with negligible differences in probability are often settled outside the courts. With the courts already recognising a need to move away from this all-or-nothing approach, at least occasionally, I suggest it is time that an all-or-nothing approach is abandoned except in cases where but for the negligence of the defendant, the claimant had at least a 90% chance of success but because of the defendant’s negligence, that chance for success has been reduced to no more than 10%.

An argument could be made that such an all-or-nothing approach provides much needed legal certainty to both claimants and defendants. While this certainty argument may be true, there is a counterargument that it is unjust for both claimants and defendants. If but for the defendant’s negligence, the claimant would have had a 40% chance of success but due to the defendant’s negligence, that chance has been reduced to 10%, it seems unfair and unjust that a claimant would recover absolutely nothing. While this essay is focused on the particular unfairness for the claimant, I do want to note that the reverse of this is true. If the defendant’s negligence resulted in a probability of, say, 55% that the claimant would suffer damages, it appears unfair that this same defendant will be liable for the same damages as if their negligence had resulted in a 95% chance of causing damages. I therefore suggest that a scaled or balanced approach ought to be adopted to reflect the probability of the defendant’s negligence resulting in damages. Furthermore, I suggest that this would not have a negative impact on legal certainty, as claimants and defendants would be able to assess the likelihood of the claim succeeding and the probability that the claimant would suffer damages and behave accordingly. Of course, this is irrelevant where the damage has already occurred, as it can be proved with 100% certainty in such circumstances that the defendant’s negligence did in fact cause damage to the claimant.

From a public policy standpoint, it was suggested by Lord Nicholls in Gregg v Scott[9] that allowing a diminution in prospects approach would increase the burden on the public purse and result in higher costs to the National Health Service. However, I suggest that if damages were awarded proportional to this loss of chance or diminished prospects, then in cases where the probability rested at, say 60%, this would result in lower costs to the National Health Service because the all-or-nothing approach would be eliminated. The cost of claims for loss of chance below 50% would be recovered by discounting claims above 50% on a proportional basis.

Keeping the Floodgates Closed: Allowing Loss of a Chance Recovery Would Not Overwhelm the Courts

If loss of a chance claims were allowed in cases of professional negligence, claimants would likely more often be awarded damages. However, as noted by Lord Briggs in Perry v Raleys Solicitors[10], ‘most claims with evenly balanced prospects of success or failure are turned into money by being settled, rather than pursued to an all or nothing trial.’ I suggest that allowing loss of a chance claims and awarding damages proportional to the chance which was lost would not result in more claims for the courts. It may, and likely would, result in more claims being settled outside the courts and would not result in an overwhelming of the court system. In cases of medical negligence, for example, lawyers could negotiate damages settlements based on the chance of the claimant’s recovery. In other cases of professional negligence, lawyers could look to precedent and assess the likelihood of a more positive outcome for the claimant but for the defendant’s negligence. Lord Nicholls in Gregg v Scott[11] said in obiter ‘” Floodgates” is not a convincing reason for letting injustice stand unremedied. This reason is invariably advanced whenever a development of the law is under consideration.’ While it could be argued that it may be appropriate to leave it to Parliament to adopt this change in the law, I do not believe that expanding the loss of a chance approach is so far a departure from the current state of law that the courts could not move in this direction.


The current case law in England and Wales relating to loss of a chance is too restrictive for claimants and does not provide additional legal certainty which could not be obtained through adopting a proportional loss of a chance doctrine. The gap between contract and tort law has been left too wide and ought to be bridged by adopting the loss of a chance approach under tort law, albeit in circumstances where elements of a contractual relationship are concurrently present (i.e., in cases of professional negligence). This would increase legal certainty and fairness to claimants by allowing claimants to recover damages proportional to their loss of a chance. This could be done using an approach evolving from that which was noted by Mrs. Justice Obi in Kingsley Napley LLP v Harris[12] where a claimant could recover for a lost chance so long as the chance that was lost was more than 10%. As noted by Lord Nicholls in Gregg v Scott[13], the floodgates argument is not sufficient to justify preventing claimants from recovering for loss of a chance, and is in fact often used to prevent evolution of the law.


Allied Maples Group Ltd v Simmons & Simmons [1995] 1 WLR 1602

Davies v Taylor [1974] A.C. 207

Gregg v Scott [2005] UKHL 2

Hotson v East Berkshire Health Authority [1987] AC 750

Kingsley Napley LLP v Harris [2021] EWHC 901 (QB)

Morris-Garner v One Step (Support) Ltd [2018] UKSC 20

Perry v Raleys Solicitors [2020] AC 352

[1] [1987] AC 750, [768] [2] [2021] EWHC 901 (QB), [6]-[7] [3] Allied Maples Group Ltd v Simmons & Simmons [1995] 1 WLR 1602 [4] Perry v Raleys Solicitors [2020] AC 352 [5] [1987] AC 750 [6] [2018] UKSC 20 [7] [1974] A.C. 207, [213] [8] [2019] UKSC 5, [17] [9] [2005] UKHL 2, [52] [10] [2019] UKSC 5, [17] [11] [2005] UKHL 2 [12] [2021] EWHC 901 (QB), [6]-[7] [13] [2005] UKHL 2

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