The Supreme Court in the case of Ministry of Defence v AB and others [2012] UKSC 9 considered a number of questions concerning the law of limitation; the central question being the interpretation of 'knowledge' for the purpose of sections 11 and 14 of the Limitation Act 1980 (the "Act").  

The appeal was dismissed by a 4:3 majority amid profound disagreement between the Lord Justices of the Supreme Court over this fundamental principle. The majority affirmed the prevailing line of authorities. Though the facts of the case were somewhat unusual the judgment is significant not only for the law of personal injury, but for any tortious claim in which the state of a claimant's knowledge under the Act is a live issue.  


The case concerned group litigation brought by a number of former servicemen (the "veterans") who suffered from a range of conditions including cancer and infertility. The veterans claimed that their conditions were the result of their alleged exposure to radiation during nuclear weapon testing carried out by the Ministry of Defence (the "MOD") in the Pacific between 1952 and 1958 (the "Pacific Tests"). Proceedings were commenced in 2006 and ten cases were selected to be tried as lead cases. Mr Justice Foskett, sitting in the Queen's Bench Division, heard limitation as a preliminary issue in a hearing lasting ten days and in which a considerable volume of factual evidence was put forward by both sides.  

Decision of the High Court

The MOD argued that each of the ten claims was statute-barred on the basis that the veterans possessed, more than three years prior to issuing proceedings, the knowledge of the necessary facts about their claim required under the Act. In respect of personal injuries, section 11(4) of the Act provides that a claim must be brought within a period of three years from: (a) the date on which the cause of action accrued; or (b) the date of knowledge (if later) of the person injured. Section 14 of the Act stipulates the knowledge which a claimant must possess for time to run against them under section 11(4)(b). The relevant subsection for the purposes of the proceedings was section 14(1)(b) which provides that a claimant must know that his injury was attributable in whole or in part to the act or omission of the defendant.  

The MOD argued that the veterans knew that their injuries were attributable to their exposure to the Pacific Tests, whilst at the same time denying that the veterans' injuries were in fact caused by the Pacific Tests. It was the veterans' case that only after they had sight in 2007 of a scientific report (the "Rowland Report"), linking chromosomal changes with exposure to nuclear radiation produced by weapons testing, that they had the requisite knowledge for the purposes of the Act. The veterans were thus in the unusual position of contending that they did not possess the required knowledge concerning their claim until a considerable period after they had issued proceedings.  

Foskett J stated his 'preferred view' was that the veterans could not be said to possess the knowledge required to start time running until they had some factual basis for concluding that their injuries were capable of being caused by their exposure to the Pacific Tests. The judge stated that this could not have taken place until the veterans had been made aware of the Rowland Report. However, he accepted that the authorities in this area did not allow him to apply his preferred view and thus found that five of the claims were statute-barred and the remaining five were not. In respect of the five cases in which the limitation period had expired he ruled that those claims should be allowed to proceed by the exercise of the Court's discretion under section 33 of the Act. Section 33 provides that in cases of personal injury the Court may disapply the limitation period where in all the circumstances it appears equitable to do so, taking into account a series of specified factors, including the length of, and the reasons for, the delay on the part of the claimant, the cogency of the evidence available, the conduct of the defendant, the extent to which the claimant acted promptly and reasonably once he knew of the attribution of his injuries and the steps taken by the claimant to obtain expert advice about his claim.  

Decision of the Court of Appeal

On appeal by the MOD the first instance decision was reversed. The Court of Appeal held that all but one of the 10 lead cases were statute-barred. The Court of Appeal also reversed Foskett J's decision on the application of section 33 of the Act. It was accepted by Counsel for the veterans that there was insufficient evidence in the Rowland Report to enable the veterans to prove causation on the balance of probabilities. Therefore, when considering the application of section 33, the Court of Appeal found that Foskett J had not given due weight to a broad merits test and the prospect that the claims were unlikely to succeed in the event that the time bar was to be disapplied. Having regard to the available evidence going to causation and the difficulties this created for the veterans' claims the Court of Appeal held that it would be inequitable to exercise its discretion under section 33 in order to allow the claims to proceed.  

Decision of the Supreme Court

The Supreme Court considered on appeal the following issues:

  1. What is meant by knowledge for the purposes of sections 11 and 14 of the Act (the "Knowledge Issue")?
  2. In the event that the veterans' claims were statute-barred, should the Court exercise its discretion under section 33 to allow the claims to proceed (the "Discretion Issue")?
  3. In the event that the claims were to proceed, should the Court extend the principles in Bonnington Castings Ltd v Wardlaw1 and/or Fairchild v Glenhaven Funeral Services Ltd 2, such that for the purposes of succeeding on causation it should be sufficient for the veterans to show that their exposure to the Pacific Tests had led to a material increase in the risk of them suffering from the injuries of which they complained (the "Causation Issue")? The appeal was dismissed by a 4:3 majority consisting of Lord Walker, Lord Wilson, Lord Brown and Lord Mance in the majority. Lord Phillips, Lady Hale and Lord Kerr delivered robust dissenting judgments, fundamentally disagreeing with the approach of the majority on the Knowledge Issue. The main judgments for the majority and minority were given by Lord Wilson and Lord Phillips respectively.  
  1. The Knowledge Issue

A fundamental division of principle separated the majority and the minority of the Supreme Court. In essence the issue in dispute was whether or not a claimant must be in possession of factual evidence in order to have 'knowledge' within the meaning of the Act. The majority held that a claimant need only have a "reasonable belief" concerning the attribution of his injuries such that it is reasonable for him to take steps to investigate whether or not he has a claim against the defendant. The majority reasoned that factual evidence is not a necessary part of a "reasonable belief". The minority adopted an entirely contrary approach, arguing that it is a claimant's knowledge and not their belief which is relevant, and that by definition knowledge must be based on fact.  

The Reasoning of the Majority

A line of prior authorities provided that the issue of a claimant's knowledge concerning the attribution of his injuries for the purposes of section 14(1)(b) is a low evidential bar to satisfy: a claimant need only know that there is a "real possibility" that their injury resulted from the defendant's conduct, as opposed to such a possibility being merely fanciful. In this respect a claimant can have knowledge of the attribution of their injury without being able to discharge the burden of proof required to demonstrate that the defendant did in fact cause their injury.  

The issue which most starkly divided the approach of the majority of the Supreme Court from the minority was whether, for the purposes of satisfying the requirements of the Act, a "belief" by the claimant that their injury was attributable to the defendant's conduct could be equated with "knowledge" that this was the case and that therefore time would start to run.

The majority held that a claimant will be deemed to have knowledge under the Act where that claimant holds a belief with a degree of confidence and substance (as opposed to mere suspicion) such that they hold a “reasoned belief” or a “reasonable belief”. Such a belief would be reasonable where it was held "with sufficient confidence to justify embarking on the preliminaries to the issue of a writ, such as submitting a claim to the proposed defendant, taking legal and other advice and collecting evidence".  

A claimant does not need to be in possession of factual evidence to substantiate their belief on the balance of probabilities. As Lord Brown succinctly put it, the focus of the prior authorities on the concept of a "reasonable belief" was “not so much on whether or how far the belief is evidence-based, but more on whether it is held with a sufficient degree of confidence to justify embarking on the preliminary to making a claim”.  

The search for a claimant's knowledge therefore involves an enquiry into that claimant's state of mind. While the majority were clear that a claimant will not automatically be deemed to have knowledge of their claim if they consult a solicitor, that inference may be justified on the facts. Once the required belief has arisen it is irrelevant if, upon consulting an expert, the claimant is told that it is not possible to prove causation. As Lord Wilson put it, a lack of evidence concerning causation could not result in claims being “put on ice...for an indefinite period, in the hope that one day the right evidence might turn up”. On a review of the evidence provided by the nine veterans, he concluded based on their private and public statements about their injuries that their claims were time barred.  

The Reasoning of the Minority

The minority for the most part adopted the reasoning underlying the “preferred view” of Foskett J, that knowledge and belief are fundamentally different concepts which should not be conflated. A belief, however strongly it may be held, which is not grounded on evidence or based upon "objective fact" is irrational, and should not be sufficient to start time running against a claimant. Lord Phillips and Lady Hale held that even the Rowland Report did not offer the veterans a sufficiently firm factual basis for their beliefs, and therefore that time still had not started to run against them.  

  1. The Discretion Issue

The majority agreed with the Court of Appeal that it was not justifiable to allow the veterans' claims to proceed by the exercise of the Court's power under section 33. Lord Wilson reiterated that it is generally undesirable for a Court, when addressing limitation issues, to consider the overall prospects of whether a claimant's case would succeed at trial. However, the circumstances of this case were unusual in that the volume of evidence which had been put before Foskett J meant that the Court of Appeal was in the rare position of having sufficient material before it to properly assess the prospects of the veterans succeeding at trial. In these exceptional circumstances, Lord Wilson found it would be wrong to allow the claims to proceed when the next step was likely to be an application to strike out the claims for lack of evidence.  

  1. The Causation Issue

The Supreme Court rejected the veterans' argument that the principle in Bonnington Castings/Fairchild should be applied to their case such that they need only show that the MOD's actions had materially increased the risk of their injuries developing. This argument was rejected on the basis of the judgment of the Supreme Court in Sienkiewicz v Greif (UK) Ltd 3.  


The facts of the case before the Supreme Court were unusual but the judgment does provide certainty as to how the state of a claimant's knowledge concerning the attribution of their damage is to be determined under the Act.  

Time will run where a claimant holds a sufficiently firm belief that there is a real possibility that his injuries are attributable to the fault of the defendant such that it is reasonable for the claimant to begin to investigate, regardless of whether there is insufficient factual evidence available (either directly or through taking expert advice) to enable the claimant to evidentially establish his case. As a consequence the limitation clock will run against a claimant despite the fact that, if proceedings were served, the claim would fail through lack of evidence.