The Court of Appeal case of Graves v Brouwer (2015) EWCA Civ 595 has tackled the issue of expert evidence with competing causation theories. Whilst this is not a construction case, the case will be of interest to contractors, employers and insurers of construction risks as to how the Courts resolve competing experts with compelling theories on causation or inconclusive explanations on cause.
Mr Brouwer decided to burn four A4 pages containing personal information in a narrow concrete alleyway between his house (no 11) and Ms Graves' (no 9). Mr Brouwer maintained the fire was small and controlled and he hosed down the fire leaving some ashes. Thirty minutes later a house fire started in the roof space of no 9. The Judge at first instance found that the fire was in the middle of the path. The fire experts at trial gave evidence that the only feasible mechanism of fire transfer was the generation of a "flying brand" but that the likelihood was of a low order. Mr Brouwer's wife gave evidence that there was no visible evidence of flying embers.
The Fire Brigade found that the seat of the fire was in the roof space of number 9 although they did not investigate arson as a cause. The experts were agreed that the origin had not been established. There were various potential causes of fire, and Ms Graves' expert considered it most likely that the fire was started by Mr Brouwer.
Under cross examination Ms Graves' expert conceded that on the balance of probabilities Mr Brouwer's fire could not have caused the house fire. Mr Brouwer's expert opined at Trial that the material burned would have been incapable of producing the ember required. Under cross examination he conceded that whilst improbable, on the balance of probabilities, in the absence of a finding of arson by the Court, then the alleyway fire had to be the cause.
The Judge, in expressly referring to the concession of Mr Brouwer's expert, rejected arson and found that the house fire had to have been caused by Mr Brouwer's fire in the alleyway and Ms Graves succeeded on causation. Without that concession the Judge would have found that Ms Graves had not established causation. On the facts however the Judge found that Mr Brouwer was not negligent and dismissed the claim.
The issue before the Court of Appeal was whether the Judge had erred in the approach to causation and whether Mr Brouwer was negligent.
The Trial Judge had considered the Popi M (1985) and the case law as to causation and the balance of probabilities. In the Popi M, the House of Lords (as it was) held that the Court, can find, even on the balance of probabilities, that the cause of the loss remains in doubt and that the burden of proof of causation has not been established.
The Trial Judge did not however refer to the case of Milton Keynes BC v Nulty (2013) EWCA Civ 15. In that case, the Judge found that that the most likely, or probable, cause of the fire was a carelessly discarded cigarette end by the engineer as opposed to an electrical cable fault. This was based on the view that whilst it was unlikely that an experienced electrical engineer would smoke in a no smoking area, on the facts the only other possible case was "very much less likely". The Court of Appeal held that the court had to stand back and consider whether it was satisfied that the suggested explanation was more likely than not to be true. The Court of Appeal found that the judge's finding on the facts was right in that the cause of the fire was "very much less likely" to have been the electrical cable fault than the discarded cigarette end was reached after an examination of the evidence. The rational analysis was that the cable theory was highly improbable, whilst the cigarette end theory was different in nature. There was no comparable scientific or practical improbability about it and whilst evidence was given that the engineer would not smoke, circumstantial evidence that he did so on this occasion was compelling.
It was clear to the Court of Appeal in the case that Judge's process of reasoning was fatally flawed. The Judge's reliance on one single answer from Mr Brouwer's expert as critical was wrong as the response had been to questions that invited him to express a view on matters of mixed fact and law, which was for the Judge to decide. The question was put on a false premise, namely that if arson was excluded then by definition, on the balance of probabilities, the alleyway fire had to be regarded as the cause of the house fire. The question had been put to the expert in a way which presupposed that there were only two possible outcomes, ignoring the possibility that Ms Graves had simply failed to prove the cause of the house fire.
Ultimately the Court of Appeal dismissed the appeal, upholding the judge's dismissal of the claim, but overturned the finding on causation. The court reiterated that the proper test on causation, was whether the Judge was satisfied that the suggested explanation was more likely than not to be true. In this case, she was not as she had not considered the other gaps in knowledge due to the inadequate forensic investigation after the fire. On the facts the Court of Appeal found that Mr Brouwer's answer was not one that would justify departing from the conclusions reached by the Judge had otherwise reached (namely that the Ms Graves had not proved causation), nor was the Court of Appeal prepared to reopen whether Mr Brouwer had been negligent in view of their findings on causation.
The case underlines the need for expert evidence and reiterates the possibility that if the expert evidence is not conclusive, then the claimant may not be able to prove the case on the balance of probabilities and affirms the principles reached in the Popi M and Nulty. A party should consider all the evidence, whether expert or factual, that needs to be adduced in relation to all possible causes of loss or damage to avoid running the risk that a Judge will find that the burden of proof has not been discharged.