“normally we are reasonably particular and we turn light switches off on leaving a room”
“Above the plasterboard ceilings of the rooms on the second floor was a layer of reflective-type insulation. The insulation comprised several layers of paper, foam sheets and foils. There was no other insulation in the roof space. The wiring for the ceiling lights was routed through the roof space but I found no evidence of any other cables or electrical items within the roof space. Within the roof space, close to the light fittings I found remains of the rodent poison blocks used by Mr Nightingale. All of the blocks were situated in close proximity to the edge of the hole into which the halogen downlighter was recessed… I found charring to one of the rodent blocks in an undamaged section of the roof space and therefore it is clear that the charring was caused by heat from the halogen bulb as opposed to the fire. I do not know whether the heat from the bulbs would be sufficient to ignite the blocks or only to char them but testing might enable me to establish this.”
“I consider the most likely cause of the fire to be associated with the halogen light fittings; either an incendive electrical fault or nearby combustible materials (such as rodents, fly, insulation, timber or the rodent blocks) being ignited by radiant and/or conducted heat from the halogen bulbs. Given that Mr Nightingale was the last person to work in the roof space and there had been no reported problems before his visit it is possible that the cause of the fire was associated with his actions (such as placing one of the rodent poison blocks on top of one of the light fittings or moving insulation). …I will arrange to carry out tests with the halogen light fittings, insulation and poison blocks in an attempt to establish whether heat from the halogen bulb would be sufficient to ignite the poison blocks and/or insulation.”
“4. …In the vast majority of cases where the judge has before him the issue of causation of a particular event, the parties will put before the judges two or more competing explanations as to how the event occurred, which though they may be uncommon, are not improbable. In such cases, it is, as was accepted before us by the appellants, a permissible and logical train of reasoning for a judge, having eliminated all of the causes of the loss but one, to ask himself whether, on the balance of probabilities, that one cause was the cause of the event. What is impermissible is for a judge to conclude in the case of a series of improbable causes that the least improbable or least unlikely is nonetheless the cause of the event; such cases are those where there may be very real uncertainty about the relevant factual background (as where a vessel was at the bottom of the sea) or the evidence might be highly unsatisfactory. In that type of case the process of elimination can result in arriving at the least improbable cause and not the probable cause. … As a matter of common sense it will usually be safe for a judge to conclude, where there are two competing theories before him neither of which is improbable, that having rejected one it is logical to accept the other as being the cause on the balance of probabilities. It was accepted in the course of argument on behalf of the appellant that, as a matter of principle, if there were only three possible causes of an event, then it was permissible for a judge to approach the matter by analysing each of those causes. If he ranked those causes in terms of probability and concluded that one was more probable than the others, then, provided those were the only three possible causes, he was entitled to conclude that the one he considered most probable, was the probable cause of the event provided it was not improbable.”
“34. … Consideration of such a case necessarily involves looking at the whole picture, including what gaps there are in the evidence, whether the individual factors relied upon are in themselves properly established, what factors may point away from the suggested explanation and what other explanation might fit the circumstances. As Lord Mance observed in Datec Electronics Holdings Limited v UPS limited[2007] 1 WLR 1325 , at 48 and 50, there is an inherent risk that a systematic consideration of the possibilities could become a process of elimination ‘leading to no more than a conclusion regarding the least unlikely cause of loss’, which was the fault identified in The Popi M. So at the end of any such systematic analysis, the court has to stand back and ask itself the ultimate question whether it is satisfied that the suggested explanation is more likely than not to be true. The elimination of other possibilities as more implausible may well lead to that conclusion, but that will be a conclusion of fact: there is no rule of law that it must do so.”
“114. It is therefore common ground between the parties in principle that in a competing theories case: a) The court is entitled to engage in a systematic analysis of competing theories and eliminate one in favour of the other; b) That, in itself, may lead to the conclusion that the preferred theory is more likely than not to be true; but c) The court must always then stand back and ask itself the ultimate question as to whether or not the preferred explanation is more likely than not to be true.”