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Legal Mind Case and Commentary No 16: Uncertainty in Judicial Decision Making: A Case to Answer? - Dr Hugh Koch, Dr Lorna Livingstone & Dr Sophie Mayhew, Hugh Koch Associates

21/08/17. Case: Kennedy v. London Ambulance Service Trust (LAS) 2016 QBD

This complex case reviewed in June’s edition of PIBULJ (Johnson and Jacobson, 2017) illustrates interesting medico-legal points about causation and attribution.

The claimant was employed by LAS as a sole responder, a role she had undertaken for 10 years. Following leaked carbon monoxide fumes from her car’s exhaust system she contracted carbon monoxide (CO) poisoning and went off sick in April 2011. She returned in September 2011 in an administrative role, and then as a joint responder due to ongoing psychological problems. Her employment was terminated in April 2015 as the joint situation could not be continued. The claimant brought a Personal Injury claim against LAS.

Liability was accepted – the primary issue was whether, and to what extent, her psychological symptoms were caused by her CO poisoning experience (it was accepted that she had a chronic psychiatric condition). This was exemplified in the debate between PTSD diagnosis and predominant attribution (claimant case) versus underlying vulnerability and non-causal link to index events (defendant case), citing pre-April 2011 entries in records for depression and stress, and immediately pre-existing family ill health stress (child speech/autistic problem).

Issues raised included:

  1. Ability to work Oct 2011 to 2015

  2. Inconsistency of suffering loss of confidence to work

  3. Low level of immediate pre-incident symptomatology

Reliance on other case law

Reference was made to Bailey vs. MOD (2008) EWCA and Dickens V. O2 PLC (2008) EWCA in which the Court of Appeal stated full damages are payable where the causative event made a material contribution, and injury is indivisible (i.e. not apportionable).

The issues were as follows: -

  1. The primary issue concerns the question of whether and to what extent the Claimant’s psychiatric symptoms were, on a balance of probabilities, caused wholly or materially by her exposure to CO poisoning in April 2011.

  2. The case for the Claimant is that it was a profound life changing experience particularly for a person who was trying at the time to cope with other stresses in her life, and that she developed as a consequence a post-traumatic stress disorder (PTSD) that continues to this day.

  3. The case for the Defendant is that the effect of the incident on the Claimant’s psychiatric wellbeing was much less severe, that her problems are attributable to her underlying vulnerability to stress and that symptoms that post-date her return to work are not causally linked to the event.

The judge came to the following conclusions, each of which have interesting commentary to make here:

  1. He was satisfied that there was evidence that:

    1. The claimant developed PTSD as a result of her experiences on the 12th April 2011;

    2. She continues to suffer from the condition;

    3. Her present condition is the result of the incident; and

    4. With appropriate treatment she should be able to return to employment in a less stressful environment in about two years’ time.

  2. He found that the claimant was a ‘person with a vulnerable personality and complex presentation’

  3. He considered if ‘the claimant’s pre-existing symptoms were such that, whilst the incident on the 12th April 2011 may have acted as a trigger, if it had not been that event, something else is likely to have happened anyway in the near future with the same result’.

  4. His substantive comments were as follows: -

a) “In my view what is significant is that the Claimant had demonstrated the fortitude in the past to cope with other stress factors in her life, and she did so, also, after she returned to work in September 2011. In the period from then until the termination of her employment, there are entries of unpleasant and distressing incidents at work, with which she coped”.

b) He stated that: -

“I think the position was well summarised by Dr Howard in his report”. Having reviewed the material, he said –

“It is my view that at the time of the accident in April 2011 Mrs Kennedy was leading a normal, stable working, domestic, social and recreational life, was essentially in good physical health and although she had shown some evidence of anxiety and depression in the face of stress in the past, there is no reason for thinking that when the accident occurred she was at risk of developing any significant psychiatric disorder in the absence of some new major intercurrent source of stress.”

He stated that: -

“Mr Stagg sought to argue, on the basis of the decision in KR v Bryn Alyn (Holdings) Ltd (2003) EWCA Civ 84 that it was appropriate to make an apportionment between the psychiatric harm that the Claimant would have suffered in any event and the harm that she has suffered in consequence of the CO poisoning incident. The Bryn Alyn case, though, concerned someone who was already psychiatrically damaged and then suffered further psychological harm in consequence of his abusive treatment in a residential home. There the psychological injury was divisible and apportionment of the damages was possible. This is a wholly different case on its facts. In Bailey v Ministry of Defence [2008] EWCA Civ 883 and Dickens v O2 PLC [2008] EWCA Civ 1144 the Court of Appeal said that where the injury to which it leads is indivisible, apportionment ‘across the board’ is inappropriate (see in particular the judgment of Smith LJ in Dickens).”

d) He stated that: -

“This principle has recently been endorsed by the Privy Council in the case of Williams v The Bermuda Hospitals Board [2016] UKPC 4. Lord Toulson quoted, with approval a passage from Professor Sarah Green’s book, “Causation in Negligence”

“It is trite negligence law that, where possible, defendants should only be held liable for that part of the claimant’s ultimate damage to which can be casually linked… it is equally trite that, where a defendant has been found to have caused or contributed to an indivisible injury, she will be held fully liable for it, even though there may well have been other contributing causes…”

e) In his opinion, the present case was, though, not so much a material contribution case as a simple “but for” case; but for the event on the 12th April, it is unlikely that the Claimant would have suffered a major psychological disorder in the foreseeable future. 


Causation and attribution are complex mechanisms which require a high degree of logicality. Key issues from a psychological and medico-legal perspective are as follows:

  1. What symptoms, physical or psychological, were evident and reported to a medical professional in the 12 month period prior to the index event?

  2. If a vulnerability or predisposition was in the claimant’s history, does research or clinical evidence predict that further episodes of these particular symptoms would emerge at this particular time (i.e. immediately post-index event) or at a later time (e.g. 3 years hence)?

  3. Applying the ‘but for’ principle, would the presenting symptoms have been predicted i.e. probable, if the index event had not occurred?


Dr HCH Koch (2016) Legal Mind: Contemporary Issues in Psychological Injury and Law. Expert Witness Publications. Manchester.


Dr Hugh Koch, Dr Lorna Livingstone and Dr Sophie Mayhew, Hugh Koch Associates, Cheltenham, Gloucestershire, United Kingdom.

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