The fact that the deceased, who was clearly determined to put an end to his own life, was able to achieve his aim so quickly despite being kept under observation by the custody officer was due to defects in the door of his cell. The wicket gate, or drop-down service hatch, on the cell door had been left open and the glass was missing from the spy hole above the wicket gate. The deceased had taken the opportunity of tying his shirt through the spy hole in order to form a ligature, with which he was then able to strangle himself. A Home Office circular of 10 April 1968 had warned police authorities and police officers of the need to ensure that fittings in cells should not provide opportunity for a prisoner to do himself injury. It had stated that, where cell doors were fitted with a drop-down service hatch, the hatch should not be left open when the cell was occupied by a prisoner, as with the hatch open it would be possible for a person inside the cell to secure a ligature on the handle of the hatch. In the present case the deceased did not need to use the handle, as the open spy hole provided him with an even more effective means of securing his ligature.

    The Commissioner accepts that he owed a duty of care to the deceased while he was in police custody. He also accepts that he was in breach of that duty, as the wicket gate was left open when the deceased was in the cell. But he submits that, as the deceased was of sound mind, his suicide in these circumstances did not give rise to a liability to his estate in damages. He seeks to distinguish this case from Kirkham v. Chief Constable of the Greater Manchester Police [1990] 2 Q.B. 283, where the person who committed suicide was held to have been suffering from clinical depression when he took his own life while in police custody. His arguments on liability been maintained in your Lordships' House on three grounds: volenti non fit injuria, novus actus interveniens and contributory negligence.

    In my opinion it is necessary at the outset to identify the duty which was owed to the deceased by the Commissioner. There is no doubt that the Commissioner was right to concede that he owed a duty of care to the deceased while he remained in police custody. The deceased had been identified as a suicide risk, having on two previous occasions attempted to strangle himself with a belt after being placed in a cell. It was the Commissioner's duty to take reasonable care not to provide him with the opportunity of committing suicide by making use of defects in his cell door. The risk was not that he would injure himself accidentally if given that opportunity, but that he would do so deliberately. That is the nature of an act of suicide by a person who is of sound mind. It is a deliberate act of self-destruction by a person who intends to end his own life. So I think that the Commissioner's duty can most accurately be described as a duty to take reasonable care to prevent the deceased, while in police custody, from taking his own life deliberately.

    It is unusual for a person to be under a duty to take reasonable care to prevent another person doing something to his loss, injury or damage deliberately. On the whole people are entitled to act as they please, even if this will inevitably lead to their own death or injury. As a general rule the common law duty of care is directed towards the prevention of accidents or of injury caused by negligence. The person to whom the duty is owed is, of course, under a corresponding duty to take reasonable care for his own safety. If he is in breach of that duty, his damages may be reduced on the ground of his contributory negligence. But if he injures himself by intentionally doing deliberately the very thing which the defendant is under a duty to prevent him doing negligently, he may find that he is unable to recover any damages. He may be found to have assumed the risk of injury, on the principle of volenti non fit injuria. Or it may be held that the chain of causation was broken by his deliberate act, in which case his claim will be defeated on the principle of novus actus interveniens. Or it may simply be that his loss, injury and damage will be held to have been caused wholly by his own fault, with the result that there will be no room even for a reduced award on the ground of contributory negligence.

    But the duty of care may sometimes extend to preventing people injuring themselves deliberately. The person to whom the duty is owed may be unaware of the risks to which he will expose himself by his deliberate act. Or he may be too young to appreciate them, as in Yachuk v. Oliver Blais Co. Ltd [1949] A.C. 386, where petrol was sold to a child aged nine who was unaware of its dangerous properties, or Hughes v. Lord Advocate [1963] A.C. 837, where the inquisitive children meddled with objects in the unattended shelter in the roadway without thought as to the consequences. Or he may be of unsound mind, with the result that he is at risk of doing something to himself which no rational person would do as he would appreciate that to do this would inevitably lead to injury. Or the risk that the person may commit an act of deliberate self-harm may be the result of something which the defendant has done or is doing to him.

    That is the situation which may arise where a person who is of sound mind is deprived of his liberty and put in prison or detained in custody by the police. The duty of those who are entrusted with his custody is to take reasonable care for his safety while he remains in their hands. If it is known that he may engage in self-mutilation or suicide while he is in their custody, their duty is to take reasonable care to prevent him from engaging in these acts so that he remain free from harm until he is set at liberty. This duty is owed to the prisoner if there is that risk, irrespective of whether he is mentally disordered or of sound mind. It arises simply from the fact that he is being detained by them in custody and is known to be at risk of engaging in self-mutilation or of committing suicide. If the prisoner, while of sound mind, destroys himself despite all reasonable precautions to prevent him doing so, there is no liability: see Pallister v. Waikato Hospital Board [1975] 2 N.Z.L.R. 725, where the board was held not to have been negligent; Pretty on Top v. City of Hardin, (1979) 597 P.2d 58, where there was no evidence that the cause of the prisoner's suicide was anything other than his own intentional act; Sudderth v. White (1981) Ky. App. 621 S.W. 2d 33. But it is hard to see why liability should not follow if the prisoner was a known suicide risk and precautions which could have been taken to prevent a deliberate act of suicide were not taken by the police.

    This brings me to the first of the three arguments which the Commissioner has advanced in his defence, which is volenti non fit injuria. I do not see how that principle can be applied to a case where the loss, injury or damage was caused by the deliberate act of self-harm which the defendant was under a duty to take reasonable care to prevent. The situation would be different if a defendant who was under a duty to prevent the plaintiff from sustaining injury by accident or negligently was faced with a claim for damages arising from an injury which the plaintiff, in full knowledge of the risks, had done to himself deliberately. It might then be said that he had voluntarily assumed the risk of injury. But that is not this case. The deceased did to himself the very thing that the Commissioner was under a duty to take reasonable care to prevent while he remained in his custody. It is true that he deliberately exploited the situation which had been created by the Commissioner's negligence. But that was the thing which the Commissioner was under a duty to prevent, as it was the foreseeable consequence of his acting negligently.

    Similarly, I do not see how what occurred in this case could be said to amount to a novus actus interveniens. There was no "new" act here at all. The act by which the deceased killed himself was the very act which the Commissioner was under a duty to prevent by not leaving the wicket gate open when the deceased was in his cell and thus providing him with the means of hanging himself. The chain of causation was not broken. There was no "third factor", as explained by Hart and Honore, Causation in the Law, 2nd ed. (1985), p. 134, which might have negatived a causal connection between the wrongful act and the harm to the deceased. Here the wrongful act was the cause of the harm because it created the opportunity for the deliberate act of self-harm. The suicide was a foreseeable consequence of the failure in duty which occurred when the deceased, who was a known suicide risk, was placed in a cell which provided him with the opportunity to carry out that act.

    Support for this view can be found in cases from New Zealand, the United States and Canada. In Pallister v. Waikato Hospital Board [1975] 2 N.Z.L.R. 725, 742 Woodhouse J., who dissented on the question whether there was evidence that the Board were negligent, rejected the argument that the voluntary act of the deceased in throwing himself from the window of the hospital was a new and independent cause of his death. He said that in his opinion it was not, because it had been made possible by the removal of the precautions. The fall was the product of the Board's negligence, not independent of it. In Moulton v. City of Cleveland, 839 F.2d 240 (6th Cir. 1988), it was held that, as the deceased's suicide was well within the scope of the risk and was foreseeable, it was not an independent intervening cause resulting in no liability. In Funk v. Clapp, (1986) 68 D.L.R. (4th) 229, Seaton J.A. said that the doctrine of novus actus interveniens could not aid the defendants in that case, where the deceased had committed suicide in his cell by hanging himself from the top of his cell door with his own belt two hours after he had been arrested, on the ground that the act of negligence consisted in the failure to take reasonable care to guard against the very thing that happened: Stansbie v. Troman [1948] 2 K.B. 48, 51-52, per Tucker L.J.. There was evidence that the police were in breach of their duty, as they should have removed his belt before he was placed in the cell and checked at intervals to see if he was all right.

    There remains the question whether the damages should be reduced on the ground of contributory negligence and, if so, what should be the extent of the reduction. The first question raises an issue of statutory construction as well as an issue of principle. Section 1(1) of the Law Reform (Contributory Negligence) Act 1945 provides:

 "Where any person suffers damage as the result partly of his own fault and partly of the fault of any other person or persons, a claim in respect of that damage shall not be defeated by reason of the fault of the person suffering the damage, but the damages recoverable in respect thereof shall be reduced to such extent as the court thinks just and equitable having regard to the claimant's share in the responsibility for the damage. . ."

The word "fault" is defined by section 4 of the Act in these terms:

 "negligence, breach of statutory duty or other act or omission which gives rise to a liability in tort or would, apart from this Act, give rise to the defence of contributory negligence."

The question is whether this definition extends to a deliberate act such as that which the deceased performed when he strangled himself with the ligature.

    It has been said that this definition of "fault" comprises two limbs: Rowe v. Turner Hopkins & Partners [1980] 2 N.Z.L.R. 550, 555 per Pritchard J., in a passage which was approved by O'Connor L.J. in Forsikringsaktielskapet Vesta v. Butcher [1989] A.C. 852, 866E-G. The first limb, which is referable to the defendant's conduct, comprises various acts or omissions which give rise to a liability in tort. The second limb, which is referable to the plaintiff's conduct, deals with acts or omissions which would, but for the Act, have given rise to the defence of contributory negligence. The first is directed to the basis of the defendant's liability, while the second is concerned with his defence on the ground that the damage was the result partly of the plaintiff's own negligence. In Mouat v. Clark Boyce [1992] 2 N.Z.L.R. 559, 564- 565 Sir Robin Cooke P. departed to some extent from Pritchard J.'s views as to the proper interpretation of the words used in the first limb. But he did not disagree with the underlying analysis, which makes it clear that the question whether the deceased was at fault in this case must be considered with reference to the words used to describe the second limb.

    Mr. Blake said that the deceased's deliberate act fell outside the scope of the common law concept of contributory negligence. It would not have provided the Commissioner with a defence to the claim of damages, as it was his duty to prevent that very same act of intentional self-harm. He submitted that the defence of contributory negligence excluded the idea of deliberation, as the defence was based on the plaintiff's failure to take reasonable care: Salmond on Torts, 10th ed. (1945), p. 451. It would be inconsistent with a rejection of the defence of novus actus interveniens, on the ground that there was no intervening act to break the chain of causation, to hold that the deceased's own act had nevertheless contributed to the harm which resulted from it.

    This argument is not without substance, for the reasons which were explained by Buxton L.J. in his discussion of this question in the Court of Appeal: [1999] Q.B. 169, 181-183. But I am unable to agree with it. In the first place, it seems to me that the consequences of this approach are unacceptable on policy grounds. It would mean that a plaintiff's award of damages could be reduced if it was held that he had contributed to his injury even to a small degree by his own negligence, but that it could not be reduced irrespective of the degree of the defendant's negligence if it was held that he had caused his own injury deliberately. This problem did not emerge until after the reform which was introduced by the Act of 1945. Until that Act introduced a new approach to the question of contributory negligence, the fact that the plaintiff's own act contributed to the damage was always a complete defence to the claim. It made no difference to the result whether his act was a negligent or a deliberate one. There was no need for the question to be explored, because there was no opportunity in either case for an apportionment of the liability in damages. But at least it can be said that no authority was cited from the law as it existed before the Act of 1945 which would make it impossible for us to say that a person was negligent, in the sense of failing to take reasonable care for his own safety, where he acted deliberately by inflicting harm on himself. That would lead to what I would regard as the proper result, which is that he should accept a share of the responsibility for the consequences.

    Next there is the analysis of the definition in section 4 into two limbs. I do not disagree with this analysis. But I think that it ought not to lead us to ignore its context, which is that of an apportionment of liability according to each party's share in the responsibility for the damage: see section 1(1) of the Act. It seems to me that the definition of "fault" in section 4 is wide enough, when examined as a whole and in its context, to extend to a plaintiff's deliberate acts as well as to his negligent acts. This reading of the word would enable the court, in an appropriate case, to reduce the amount of damages to reflect the contribution which the plaintiff's own deliberate act of self-harm made to the loss.

    The point that one should not be unduly inhibited by the use of the word "negligence" in the expression "contributory negligence" has been well made by Prosser & Keeton, Torts, 5th ed., (1984) section 65, p. 453 in a passage which appears as a footnote in Hickey v. Zezulka, (1992) 487 N.W. 2d 106, to which I refer later, at p. 123:

 "It is perhaps unfortunate that contributory negligence is called negligence at all. 'Contributory fault' would be a more descriptive term. Negligence as it is commonly understood is conduct which creates an undue risk of harm to others. Contributory negligence is conduct which involves an undue risk of harm to the actor himself. Negligence requires a duty, an obligation of conduct to another person. Contributory negligence involves no duty, unless we are to be so ingenuous as to say that the plaintiff is under an obligation to protect the defendant against liability for the consequences of the plaintiff's own negligence."

Then there is Buxton L.J.'s reference, [1999] Q.B. 169, 182E, to the warnings which have been issued on policy grounds against permitting an employer's absolute duty under the Factories Acts to be undermined by an appeal to contributory negligence, especially where the contributory negligence alleged was the very thing which the statutory duty of the employer was designed to prevent: e.g. Hutchinson v. London and North Eastern Railway Co. [1942] 1 K.B. 481, 488 per Goddard L.J. I do not think that much, if anything, can be made of this point. The need for such extreme caution is less obvious now that the complete defence which was afforded by a finding of contributory negligence has been replaced by the provisions which the Act of 1945 made for reducing the amount of damages. Cases such as Hugh v. National Coal Board 1972 S.C. 252 show that judges have no difficulty in practice in making a finding of contributory negligence where a plaintiff has deliberately disobeyed instructions which his employer, in pursuance of an absolute statutory duty, has issued to his employees.

    Further support for the view that a finding of "contributory negligence" may be made where the plaintiff has injured himself deliberately can be found in decisions in other jurisdictions in cases where damages have been claimed following an act of suicide. In Pallister v. Waikato Hospital Board [1975] N.Z.L.R. 725, 736 Richmond J. doubted whether, if it had been established that the Board failed to use reasonable care to guard Mr. Pallister against his own suicidal tendencies, that could be called the sole cause of his death as the act of the deceased in jumping from a window would possibly amount to "fault" as defined by section 2 of the Contributory Negligence Act 1947. It was unnecessary to decide the point, as it was not argued in that case. But the question has been decided, as an issue about comparative fault, in several cases in the United States.

    In Molton v. City of Cleveland, (1988) 839 F.2d 240 (6th Cir.), the city's liability for the death of a detainee who committed suicide in a cell after being beaten by police officers was reduced by 20 per cent on the ground of the detainee's comparative fault. In Hickey v. Zezulka (1992) 487 N.W. 2d 106 (Mich.), it was held that the campus police officer who had been accused of negligence after a person whom he had arrested hanged himself in a cell was entitled to an instruction at the trial on comparative fault. The judges in the Michigan Supreme Court were not unanimous as to the need for such an instruction. But the majority view was that, while the plaintiff should not lose his cause of action because the act of suicide had been committed deliberately, the court should not go to the other extreme of holding that the defendant must assume all responsibility and liability for injuries that the plaintiff intentionally commits upon himself. The majority were also of the opinion that jurors were capable of reaching a rational and sensible balance between the deceased's deliberate fault and the jailer's negligence. As Riley J. put it at p. 124, the goal of establishing a fair system of apportionment of damages is not served, rather it is thwarted, when a slightly negligent defendant is held liable for 100 per cent of the damages caused principally by the plaintiff's wrongful intentional conduct. In Champagne v. United States of America (1994) 513 N.W. 2d. 75, after examining a number of cases about comparative fault in cases of suicide including the Hickey case, the Supreme Court of North Dakota rejected the argument that, when a patient's act of suicide is a foreseeable result of a medical provider's failure to treat reasonably to prevent the suicide, it is never appropriate to compare the victim's act of suicide with the medical provider's fault. If the patient was capable of being responsible for his own care, allocation of fault was in order. But a mentally ill patient could only be held to the degree of care permitted by his diminished capacity. The worse the suicidal patient's diminished capacity, the greater the medical provider's responsibility.

    I would apply that approach to the present case. The judge found that the deceased was of sound mind. One may question whether that is an appropriate description of a person who for no obvious reason decides to end his own life. But the judge felt that he was bound to proceed on the evidence and we also must accept that evidence. So there are no grounds for minimising the deceased's share of the responsibility on the basis of diminished mental capacity. Moreover the contribution which he made to the fatal outcome was clearly a substantial one. It was not only a deliberate act. The fact that it was done so quickly, within minutes of the last check of the cell, also indicates a determination on his part immediately to seize the opportunity before the time came for the next check. On the other hand the contribution which was made by the Commissioner's fault indicates that he too must bear a substantial share of the responsibility. The defects in the cell door fell clearly within the warning in the Home Office circular. Anyone taking reasonable care to prevent the deceased from committing suicide should have appreciated that these defects would provide him with the opportunity of taking that step as soon as he was left unobserved in the cell. In all the circumstances I agree with the view expressed by Lord Bingham of Cornhill C.J. in the Court of Appeal, [1999] Q.B. 169, 198D-E, that responsibility for the suicide should be shared equally in this case between the deceased and to the Commissioner, and that the damages recoverable by the plaintiff should be reduced by 50 per cent.

    I would therefore allow the appeal and make the same order as that which has been proposed by my noble and learned friend Lord Hoffmann.

LORD HOBHOUSE OF WOODBOROUGH

My Lords,

    This appeal raises two questions. The first is whether the death of Mr Lynch was caused by the negligence of the defendant. The second is whether, assuming that it was, the defendant has a defence under the Law Reform (Contributory Negligence) Act 1945. Your Lordships would answer both questions in the affirmative. It was a forensic paradox (as confirmed by the judgment of Lord Justice Buxton in the present case) that the argument of each side on the second question was persuasive to undermine its argument on the first question. If however the first question is, contrary to my view, to be answered in favour of the plaintiff, then I see no difficulty in answering the second question in favour of the defendant nor, on that hypothesis, would I differ from your Lordships' opinion, in agreement with the preferred view of Lord Bingham L.C.J., that the reduction in the plaintiff's recoverable damages should be 50%. In this speech I will therefore confine myself to the first question, the question of causation.

    The plaintiff's cause of action arises out of the death of her former husband, Mr Lynch. She is to be taken as having sued under both the Fatal Accidents Act 1976 and the Law Reform (Miscellaneous Provisions) Act 1934. Under sections 1(1) of each of these Acts, the plaintiff is not entitled to assert any cause of action which the deceased could not have asserted if he had survived and the defendant can rely upon the defences he would have had against the deceased. (See also s.5 of the 1976 Act.) This needs to be stressed at the outset since there are indications in the judgments of both Buxton L.J. and Lord Bingham in the Court of Appeal in the present case that they were influenced by the fact that the action was being brought for the benefit, not of the deceased, but of his relatives. But it is fundamental that it is the deceased's cause of action (if any) which is being sued on. For the purposes of my discussion of causation it is both convenient and right to treat the deceased as the plaintiff. The principles of law to be applied are those which relate to the assessment of the conduct of a plaintiff as the cause of his own loss.

    The starting point in the present case is the acceptance that the defendant owed Mr Lynch a duty of care. As Lord Bingham put it, [1998] 2 W.L.R. 392, 424,

 "the defendant by his officers at Kentish Town police station owed the deceased a duty to take reasonable care to ensure that he was not afforded an opportunity to take his own life."

(This duty is an application of the more general duty to take reasonable care of a person in one's custody: Reg. v. Deputy Governor of Parkhurst Prison, Ex parte Hague [1992] 1 A.C. 58) Lord Bingham emphasised that the duty was a duty to take reasonable care and not to guarantee that a fatality did not occur. He then went on to say in two similar passages (at pp. 424-425):

 "Since an act of self-destruction by the deceased was the very risk against which the defendant was bound in law to take reasonable precautions, I cannot see how that act can be regarded as a novus actus. So to hold would be to deprive the duty of meaningful content. This was, after all, the very thing against which the defendant was duty- bound to take precautions. It can make no difference that the deceased was mentally "normal" (assuming he was), since it is not suggested that the defendant's duty was owed only to the abnormal. The suicide of the deceased cannot in my view be regarded as breaking the chain of causation."

 "If the defendant owed the deceased a duty of care despite the fact that the deceased was of sound mind, then it again seems to me to empty that duty of meaningful content if any claim based on breach of the duty is inevitably defeated by a defence of volenti."

I would draw attention to three features of these two passages. The first is that Lord Bingham apparently does not accept that any conduct of the suicide would be capable of constituting the sole legal cause of his death. The second is the peculiarity of the present case that the deceased was held by the trial judge to have been of sound mind in contrast with the finding which had been made in Kirkham v. Chief Constable of the Greater Manchester Police [1990] 2 Q.B. 283, and had formed the basis of the Court of Appeal's decision in that case. The third is the use of metaphors and Latin tags which I will suggest have outlived their usefulness and now only serve to cause confusion (a view expressed by Lord Sumner as long ago as 1915: British Columbia Electric Railway Co. Ltd. v. Loach [1916] 1 A.C. 717, 727-728).