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Session 1999-2000
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Judgments - Dingley v. Chief Constable of Strathclyde Police


Browne-Wilkinson Lord Nicholls of Birkenhead Lord Steyn Lord Hope of Craighead Lord Clyde








ON 9 MARCH 2000


My Lords,

    I have read in draft the speech prepared by my noble and learned friend Lord Hope of Craighead. For the reasons which he gives I would dismiss the appeal.


My Lords,

    I have had the advantage of reading a draft of the speech of my noble and learned friend Lord Hope of Craighead. For the reasons he gives I too would dismiss this appeal.


My Lords,

    I have had the advantage of reading in draft the speech of my noble and learned friend Lord Hope of Craighead. For the reasons he has given I would also dismiss the appeal.


My Lords,

    The appellant is a retired police officer. He was working in the course of his employment as a constable of Strathclyde Police on 11 April 1990 when he was injured in a road accident near the Townhead interchange on the M8 motorway. The driver of a police van in which he was travelling lost control of the vehicle. It swerved violently from side to side, overturned, spun round and landed on its roof. The appellant was thrown about as it did so. He struck his head on a wooden partition inside the vehicle and suffered a whiplash injury to his neck. He emerged from the vehicle dazed and with a sore neck but no serious injuries. He was taken to Stobhill Hospital where it was found that he had an abrasion to his scalp but that his central nervous system was intact and that he had not lost consciousness. He was discharged and returned to the police office before being sent home. Although he had a stiff neck the next day, he worked a normal shift. He was then off duty for three days. He returned to his normal duties at the start of the next week.

    The whole event would have been passed off as nothing more than a lucky escape in the course of what turned out to be a minor accident had it not been for the fact that the appellant began to develop the symptoms of multiple sclerosis ("MS") seventeen days after sustaining his neck injury. On 28 April 1990 he was on duty escorting an Orange Walk. He had been walking for about one and a half hours for a distance of two miles or so when he noticed that he was "dragging" his left leg. He felt as if his leg had gone lame. He was able to complete the march and the problem went away after he had rested. But it recurred about two weeks later when he was walking home. He had walked for about a mile when he again noticed that his left leg was dragging. He eventually had to take a taxi to get home, but once he was there his leg recovered after resting. Various other events then followed, none of which at the time seemed to be particularly significant. In July 1990 he had difficulty in maintaining his balance while strawberry picking. In August 1990 he consulted his general practitioner complaining of a stiff neck. In September 1990 he returned to his general practitioner complaining of blurring of vision while concentrating at work and of continued neck pain. But thereafter his condition began to deteriorate, as he encountered increasing problems with his leg and his balance. By the end of the year he had begun to experience problems of bladder control. In March 1991 when on a nature trail with his family he was unable to complete the walk and had to sit down.

    On 2 April 1991 he discussed these problems with his general practitioner who referred him to the Department of Neurology at the Southern General Hospital in Glasgow requesting an opinion regarding a possible diagnosis of MS. He was seen a month later in the hospital by Dr. I.T. Draper, a consultant neurologist. Various tests were done, and on 11 August 1991 Dr. Draper reported to the general practitioner that the results were strongly in favour of a diagnosis of MS. The appellant was informed on 11 September 1991 that his symptoms were probably due to this condition by a registrar in the hospital. By now his impaired mobility had become more noticeable and he had been assigned to light duties in the police force. In April 1993 he was diagnosed as suffering from depression due to ill-health. On 12 August 1993 the Chief Medical Officer of Strathclyde Police wrote to the appellant's general practitioner to inform him that steps were being taken to retire the appellant from the police force on health grounds. Thereafter his condition continued to deteriorate with tragic consequences for both him and his family. By the end of the following year he was severely disabled by the disease and had become dependant on a wheelchair for mobility. His wife had to give up her part-time work to look after him. Their only source of income was his police pension and his disability allowances.

    The possibility that the appellant's disability might be related in some way to the accident was first raised on his behalf by his solicitors in June 1991. By that time he was undergoing tests in the Southern General Hospital. His solicitors wrote to Dr. Draper on 25 June 1991 requesting a report on his treatment and confirmation that his injuries and condition were directly related to the accident. On 14 October 1991 Dr. Draper provided them with a report in which he said that, while MS was an illness which does occur spontaneously, there had been speculation for many years as to whether it might be provoked or caused to relapse by trauma. He concluded his report by saying that there was clear evidence of damage to the brain and the brain stem of the kind which was associated with MS and that, while proof was not possible to come by, it was reasonable to assume a causal relationship between the occurrence of the MS and the injury which the appellant had sustained on 11 April 1990 when he was in the police van. On 9 February 1993 Dr. William Durward, a consultant neurologist at Glasgow Royal Infirmary, prepared a report for the appellant's solicitors in which he said that, having examined the appellant and read Dr. Draper's report, he agreed that the appellant had MS and that he considered on balance of probability that there was a link between trauma sustained on 11 April 1990 and its subsequent development. On 29 March 1993 the appellant commenced these proceedings in which he claimed damages against the Chief Constable.

The proceedings in the Court of Session

    By the time when the appellant's case came to proof before the Lord Ordinary, Lord Dawson, in June 1995 the Chief Constable had admitted liability for the accident. The issue between the parties on the pleadings was focussed by the appellant's averments on the one hand that MS is a condition which may be provoked by trauma and that the trauma to his head, neck and shoulders in the accident of April 1990 had resulted in the development of his MS, and by the Chief Constable's averments on the other that MS is not a condition that is caused or influenced by trauma and that any trauma sustained by the appellant in the accident of April 1990 did not cause his MS.

    Dr. Draper and Dr. Durward both gave evidence in support of the appellant's case, but they made it clear that they were not qualified to engage in a detailed debate on this subject as their primary concern had always been with the practical problems relating to the diagnosis and treatment of MS. In this situation detailed evidence on the critical issue as to the causal relationship, if any, between the appellant's accident and his development of the symptoms of MS was left to two rival teams of eminent expert witnesses. The appellant's experts were Professor Peter Behan, Professor of Neurology at the University of Glasgow, and Dr. Charles M. Poser of the Harvard Medical School and Beth Israel Hospital, Boston. Those for the Chief Constable were Professor D.A.S. Compston, Professor of Neurology at the University of Cambridge, Professor William A. Sibley, Professor of Neurology of the University of Arizona and Dr. Leonard T. Kurland, Senior Consultant at the Mayo Clinic, Rochester, Minnesota.

    It was not possible to complete the proof in June 1995 and further evidence was held in December of that year. On 6 November 1996 the Lord Ordinary pronounced an interlocutor in favour of the appellant and awarded him £547,250 as damages. The Chief Constable reclaimed, and on 5 March 1998 the First Division (the Lord President, Lord Prosser and Lord Caplan) allowed the reclaiming motion with the result that the appellant's award was reduced to £1,500 which was agreed as the solatium due to him for the injuries which he received in the accident: 1998 S.C. 548. The appellant has now appealed to your Lordships' House against the First Division's interlocutor.

    It is necessary at this point to mention two features of the way in which this case was dealt with in the Court of Session, as they have had a profound bearing on the nature of the material which is before your Lordships in this appeal. The first is that, while the Lord Ordinary's opinion provides a useful and accurate summary of the factual background and of the evidence given by the expert witnesses, it lacks any analysis of their evidence. Much of it was the subject of detailed criticism by the witnesses on both sides. But it is impossible to tell what the Lord Ordinary made of those criticisms as he has failed to explain the grounds on which he decided to accept some parts of the evidence and to reject other parts, as he must have done in order to find the appellant's case proved. There is no indication that he based his decision to any extent on the demeanour of the witnesses when they were giving evidence, although he noted - as is indeed obvious from the transcript - that Professor Behan and Professor Compston in particular both held strong views on the points which were at issue and were at pains to express them at considerable length in answers which often bore little relationship to the questions which had been asked. The exercise of his judgment was wholly dependent on an evaluation of the substance of all the expert evidence, but there is no discussion of these matters in his opinion. The First Division held that the Lord Ordinary's decision as a whole was unsatisfactory and, applying Lord Thankerton's well-known dicta in Thomas v. Thomas 1947 S.C.(H.L.) 45 at p. 54 and Lord Keith of Kinkel's observations in Stephen v. Scottish Boatowners Mutual Insurance Association 1989 S.C.(H.L.) 24 at p. 61, they decided that it was open to the Inner House to review the whole matter. The appellant accepts that they were entitled to reach this view.

    The second feature of the case is the outstanding quality of the opinions which were delivered by all the judges of the First Division, and especially - if I may say so - that of the Lord President. This has more than redressed the absence of detailed reasoning in the opinion of the Lord Ordinary. Great care has been taken to explain the anatomy and physiology which formed the background to the debate between the expert witnesses and to identify and analyse the grounds on which the propositions on each side of the argument were based. The complex nature of these issues is underlined by the fact that, although the judges were unanimous in their decision to allow the reclaiming motion, they gave different reasons for reaching this view. In the result it has been much easier than it might otherwise have been for your Lordships to identify and explore the points which lie at the heart of this appeal.

The proceedings in this House

    Section 40(1) of the Court of Session Act 1988 provides that it shall be competent to appeal from the Inner House to the House of Lords without the leave of the Inner House against a judgment on the whole merits of the cause. The decision of the Inner House in this case is such a judgment. The right of appeal to this House may be directed to issues of fact as well as issues of law. As Lord Reid said in Benmax v. Austin Motor Co. Ltd. [1955] A.C. 370, 375, apart from cases which are expressly limited to questions of law, an appellant is entitled to appeal against any finding, whether it be a finding of law, a finding of fact or a finding involving both law and fact. Appeals from the Court of Session on issues of pure fact are unusual. The House will only review concurrent findings of fact in the Outer and Inner House of the Court of Session which depend on an assessment of credibility by the trial judge if it can be clearly demonstrated that the findings are erroneous: Islip Pedigree Breeding Centre and Others v. Abercromby 1959 S.L.T. 161, 174 per Lord Reid; Brodie v. British Railways Board 1972 S.L.T. (Notes) 37, per Lord Kilbrandon. But that rule of practice cannot be applied in this case, and the appeal has been quite properly taken on what is undoubtedly an issue of pure fact. The matter is further complicated by the absence of any detailed reasoning in the opinion of the Lord Ordinary. In the result the decision of the Inner House - which is based entirely on the printed evidence - must be regarded as open to scrutiny by your Lordships in the same way as if it had been taken at first instance and was at large for consideration by the appeal court.

    But it is not practicable for the means by which such decision at first instance is normally scrutinised in the Inner House, by the reading of the evidence to the judges from the transcript and then subjecting it to argument, to be adopted by your Lordships in this House. Lord Steyn pointed out in Smith New Court Securities Ltd. v. Citibank N.A. [1997] A.C. 254, 275 that the prime function of the House of Lords in English appeals is to review questions of law of general public importance. He said that it could not properly discharge that function if it often had to hear appeals on pure fact. Similar considerations require that regard must be paid to the need for economy in the time taken in Scottish appeals to present arguments on questions of pure fact. With that in view, their Lordships took the unusual step of holding a preliminary hearing in this case to discuss the procedure which was to be adopted in the preparation of the appeal.

    An essential element in that procedure was the exchange between the parties of their written cases prior to the lodging of the final written cases in the Judicial Office. Both sides were asked to ensure, when preparing their written cases, that they set out not merely the heads of argument but also an outline of the argument to be advanced under each head and that the parts of the judges' opinions which were under challenge were clearly identified by page number. They were also asked to provide cross-references to the particular passages in the evidence or the medical reports on which they proposed to rely in support of any submission that the judges' treatment of the facts was materially incomplete, inaccurate or otherwise in need of supplementing by reference to the words used by the witnesses. Counsel on both sides are to be commended for the care and attention which they have given to these details, and for the fact that their cases gave identical paragraph numbers to the competing arguments on each point. Their Lordships were greatly assisted by the quality of the written cases in their preparation for the hearing of the appeal and in their consideration of the case after the conclusion of the oral argument.

The medical background

    As the Lord President observed at p. 558, the matters in dispute between the parties are medical. They were debated with the witnesses against the background of a shared knowledge of the relevant anatomy and physiology and of the nature of the medical conditions which were being discussed. The Lord Ordinary was at a disadvantage in dealing with these agreed matters because he was not provided with an elementary text to guide him through these chapters of the evidence. Following a suggestion which was made at the procedural hearing, a description of the anatomy and physiology of the central nervous system, a copy of the relevant chapters in Richard S. Snell's Clinical Neuroanatomy for Medical Students, 4th edition, and an excerpt from Grant's Method of Anatomy were included in the Appendix. But the best guide to the medical background is to be found in the Lord President's opinion at pp. 558-563 where he set out his understanding of these matters with great clarity and commendable attention to detail.

    It is not necessary for me to go over all the ground which he has described so fully and so well and is illustrated so helpfully by the material which was included in the Appendix. But I must mention some of the more important points described by the Lord President which were common ground among the witnesses.

    MS is a disease of the central nervous system ("CNS"). The brain and the spinal cord which together make up the CNS are connected with each other by nerve fibres. The spinal cord contains nerve cells which control movement. Signals are transmitted from the nerve cells to all parts of the body by nerve fibres. These fibres also transmit signals from other parts of the body to the spinal cord. The nerve fibres are covered in a sheath of myelin, which has an insulating effect on the electrical signals which they transmit. Damage to the spinal cord is liable to interfere with these signals and may cause paralysis. In MS the myelin which covers the nerve fibres within the CNS becomes depleted, although the nerve fibre itself remains intact. This process is known as "demyelination". When demyelination occurs the nerve fibres are deprived of their sheath, and this impairs their ability to conduct electricity. It results in the formation of plaques within the CNS which become scarred or sclerotic as they develop and get older. Symptoms occur when a plaque develops in an area which affects the operation of a sensory or motor function of a part of the body such as the arms or the legs. It is a characteristic of the disease that it affects different parts of the brain at different times. Symptoms may appear for a short period and then disappear. They may manifest themselves later in a different way because the myelin is being attacked in some other part of the CNS. In a high number of cases the disease becomes progressive and the patient suffers a decline, becoming more and more disabled as time goes on.

    There is no proof of what causes MS. But it is common ground that trauma never causes the disease. So, as the Lord President put it at p. 562, the dispute is as to whether trauma can "trigger" it. MS occurs among certain races and not others, and only certain people within these races are liable to develop it. They were referred to by the witnesses as "potential demyelinators". The consensus view is that a genetic factor is involved, and that those with the necessary genetic characteristics become potential demyelinators due to a microbial or viral infection in their childhood. Not all potential demyelinators develop symptomatic MS. For many the reason why they become symptomatic is a mystery, as its clinical manifestation starts without being preceded by any obvious event which could be said to have caused or "triggered" it. It appears to be accepted by the experts that exposure to a virus is the most common trigger. The area of dispute is whether symptomatic MS can ever be triggered by trauma.

    The body is supplied with an immune system which responds to an attack by a foreign body by producing organisms known as lymphocytes. These are of two kinds. B-lymphocytes produce antibodies which react with the foreign body and render it harmless. T-lymphocytes attack the foreign body in various ways which complement the role of the B-lymphocytes. The immune system can however work in an incorrect way. This results in its failure to distinguish between foreign bodies and other bodies from within the body against which it reacts. When the system is in this condition the activated T-lymphocytes may behave in a deranged manner in a way that is associated with the development of MS plaques.

    The organs of the CNS require to be supplied with various nutrients which are delivered by means of the blood stream. But the brain could be damaged if harmful substances were to be allowed to pass into the brain. A structure exists between the blood and the brain whose function it is to prevent this. It is known as the blood brain barrier ("BBB"). It consists of a layer of cells, each of which is opposed to the other by a tight junction. As the Lord President explains at p. 561, it is incorrect to think of the BBB as a wall or some other similar kind of barrier. It operates in a selective fashion by admitting some and excluding other substances. When it is operating normally it allows beneficial nutrients to pass into the brain but it excludes harmful substances. Among the substances which pass in and out of the brain in a healthy subject is a modest, or low-level, supply of lymphocytes. When the body is responding to an attack such as an infection the BBB alters so as to allow an increased supply of lymphocytes to pass into and out of the brain to fight the infection. A key question in the case is whether, and if so in what circumstances, trauma may also alter or open up the BBB so as to allow activated and deranged T-lymphocytes to enter the brain.

    The main chapters of evidence to which the expert witnesses turned in order to justify the conclusions which they reached on the critical issues in the case against this general background consisted of the following. For the appellant Dr. Draper, Dr. Durward, Professor Behan and Dr. Poser relied on their own clinical experience and reports of cases in the medical literature, including a summary of the reports linking trauma with the onset of MS provided by D. McAlpine and N. Compston in their epidemiological study, "Some aspects of the natural history of disseminated sclerosis", Quarterly Journal of Medicine, New Series, vol. 21 (1952), 135-167. Professor Behan and Dr. Poser relied in addition on a series of experiments on animals. Dr. Poser also drew support for his position from an article by R. Gonsette and others published in Acta Neurologica Belgica, vol. 66 (1966), 247-262 and a paper by D.R. Oppenheimer, "The cervical cord in multiple sclerosis", published in Neuropathology and Applied Neurobiology, vol. 4 (1978) 151-162. For the respondent Professor Compston, Dr. Sibley and Dr. Kurland also relied on their clinical experience. Professor Compston drew support for his conclusions from two other epidemiological studies. One, which was referred to as "the Arizona Study", was carried out by Professor Sibley and his colleagues in the Department of Neurology at the University of Arizona and was the subject of two papers: C.R. Bamford and others, "Trauma as an etiologic and aggravating factor in multiple sclerosis", Neurology, vol. 31 (1981), 1229-1234; W.A. Sibley and others, "A prospective study of physical trauma and multiple scelorosis", Journal of Neurology, Neorosurgery and Psychiatry, vol. 54 (1991), 584-589. The other, which was referred to as "the Mayo Clinic Study", was based on records from Olmstead County, Minnesota and was the subject of a paper by A. Siva and others including Dr. Kurland, "Trauma and multiple sclerosis", Neurology, vol. 43 (1993), 1878-1882.

The issues in this appeal

    The Lord President said at p. 564B that the question whether the appellant's injury caused the onset of his symptomatic MS could be broken down into two questions. The parties to this appeal adopted that approach when they were presenting their arguments. The first, or "general", question is whether trauma can ever cause, or "trigger", the onset of symptomatic MS in a susceptible individual. The second, or "particular", question is whether, if trauma can trigger symptomatic MS, it did so in the appellant's case. The word "trigger" is used to describe the mechanism that turns asymptomatic MS into symptomatic MS.

    There is however a close relationship between these two questions which requires that they be defined more precisely. The first symptom which the appellant noticed after the accident was the dragging in his left leg. There was ample evidence to show that this was a symptom of his MS, and that the disease had become symptomatic because he had developed a plaque or plaques on his spinal cord. This is because the spinal cord is an area in which the development of plaques of demyelination will produce that kind of symptom. The Lord President said at p. 565C that he was prepared to proceed on the basis that shortly after the accident the appellant had a plaque or plaques of demyelination on his spinal cord. He also said that he was satisfied that the spinal cord could have been damaged by a whiplash injury. The respondent has not challenged either of these findings, and I accept them as justified by the evidence.

    There was no direct evidence that the whiplash injury which the appellant sustained in the accident did in fact damage the spinal cord, as there is nothing in the records of the hospital where he was treated after the accident to indicate that he sustained this particular injury. For damage of this kind to occur the whiplash injury must disrupt the spinal canal within which the spinal cord is located in such a way that the cord is bruised or damaged. No X-rays were taken or other findings recorded to indicate that the appellant suffered any kind of damage to those structures in his neck. But it is possible to establish that this was so by inference, and the appellant's witnesses sought in this way to link the development of a plaque or plaques on his cervical cord to the type of injury which he sustained in the accident. The critical questions therefore are (1) whether a whiplash injury which damages the nerve pathways in the spinal cord can ever trigger symptomatic MS and, if so, (2) whether it can be inferred from the fact that the appellant developed a plaque or plaques on his spinal cord shortly after the accident that his whiplash injury was of the kind which causes damage to the nerve pathways in that area.

The reasons given by the judges in the Inner House

    I mentioned earlier that the judges of the First Division gave different reasons for allowing the reclaiming motion. In the Statement of Facts and Issues the following summary of the conclusions which they reached is given:

    "(a) the Lord President

    (i) that trauma could never trigger MS in a potential demyelinator

    (ii) that he therefore did not require to address the issue of whether trauma had brought about the pursuer's MS

    (b) Lord Caplan

    (i) that trauma could not trigger MS in a potential demyelinator

    (ii) were it to have been shown to have been probable that MS can be triggered by neck trauma, he would have been inclined to hold that the appellant was one of those with a neck injury which has caused MS

    (c) Lord Prosser

    (i) that trauma could trigger MS in a potential demyelinator

    (ii) but that it did not do so in the pursuer's case."