“We think that the legal position can be summarised as follows: (1) in all cases where a judge is asked to consider a submission of no case to answer, the judge should apply the “classic” or “traditional” test set out by Lord Lane CJ in Galbraith. (2) Where a key issue in the submission of no case is whether there is sufficient evidence on which a reasonable jury could be entitled to draw an adverse inference against the defendant from a combination of factual circumstances based upon evidence adduced by the prosecution, the exercise of deciding that there is a case to answer does involve the rejection of all realistic possibilities consistent with innocence. (3) However, most importantly, the question is whether a reasonable jury, not all reasonable juries, could, on one possible view of the evidence, be entitled to reach that adverse inference. If a judge concludes that a reasonable jury could be entitled to do so (properly directed) on the evidence, putting the prosecution case at its highest, then the case must continue; if not it must be withdrawn from the jury” (all emphasis in original). 12. The case of Broughton concerned the failure of a young man to seek help for a young woman to whom he had given a cocktail of drugs at a music festival. The Crown’s case was that he owed a duty of care to secure timely medical intervention when her condition deteriorated to the point where her life was obviously in danger. At the close of the prosecution case the defence had argued that the prosecution evidence was insufficient to prove to the criminal standard that the defendant’s negligence had been at least a substantial contributory cause of his girlfriend’s death. The submission was based upon unchallenged medical evidence to the effect that at the relevant time the negligence had deprived her of a 90% chance of survival, or put another way that there was a 10% chance that she would have died even with medical assistance. The trial judge had allowed the case to proceed and the defendant was convicted. On appeal his conviction was quashed, the court deciding that the necessary causal link between negligence and death had not been established. The medical evidence had left open a realistic possibility that the young woman would have died anyway and in those circumstances no jury could have been sure that the negligence, however gross, was a cause of death. At [23], referring to the case of R v. Gian[2009] EWCA Crim 2553 , Lord Burnett CJ said this: “[Gian] concerned a suggestion that there were theoretical or hypothetical possible causes of death which could not be excluded as a matter of theory but were entirely unrealistic. The jury must make judgments on “realistic not fanciful possibilities”
“100. It is unhelpful to attempt to contrast scientific certainty (put at 100%) with a different figure for legal certainty. Human beings asked the question whether they are sure of something do not think in those terms. In the context of causation in this very sad case the task of the jury was to ask whether the evidence established to the criminal standard that, with medical intervention as soon as possible after [her] condition presented a serious and obvious risk of death, she would have lived. In short, had the prosecution excluded the realistic possibility that, despite such treatment, [she] would have died? 101. In our judgment none of Professor Deakin’s descriptive language achieved that. Even his description of a 90% chance of survival at 21.10, were medical help available, leaves a realistic possibility that she would not have lived….. 103. In our view, this is one of those rare cases… where the expert evidence was all the jury had to assist them in answering the question on causation. That expert evidence was not capable of establishing causation to the criminal standard.” 21. The judge summarised the parties’ submissions which had focussed on the third of the three scenarios which the prosecution had accepted was “credible” and which Mr. Summerfield did not relate causally to any of the alleged breaches. It was not dealt with in any further report following the appearance of the third scenario in the Joint Statement, or in his examination in chief. In cross-examination, defence counsel illustrated this scenario by consideration of a sifting machine which was brought into operation that morning in room 1(1)(b) at the Mill, on the Forest Fresh production line. In cross-examination by Mr. Kay, Q.C. for WTL and Mr. Antrobus, Q.C. for Mr. Boden, Mr. Summerfield had accepted that it was possible that the sifting machine had malfunctioned and caused sufficient dust to become airborne in one room in the Mill to fuel an explosion of the kind which occurred. He said that this could have occurred because it was being brought back into use that morning after repair and it may not have been re-connected properly, or perhaps its flexible connectors to the rest of the process had failed, or seals had failed. If this had happened, the quantity of wood particles being sifted by it would be about ten times the quantity which would be required to cause an explosive mixture in a room of the relevant size. The time when the machine was restarted was known, as was the time of the explosion and this enabled a calculation of the amount of material being processed during that time. If the failure had been so catastrophic that all the wood material was ejected from the machine then that would be the result. He said that the risk of a machine failing when first connected to a system was a known one, and had frequently occurred in other cases. He cited Piper Alpha as an example. He agreed that such an explosion could account for the damage done to the Mill, and said that this was possible. He could not exclude it “beyond reasonable doubt”, but felt, as did Dr. Ketchell, that a secondary explosion was more likely to have been the true cause of the deaths. He set out his reasons for taking this view. 22. The evidence concerning the sifter had been elicited from factual witnesses during the prosecution case. It was apparent that the defence were exploring that possibility as an example of an event which was within scenario 3, and the facts thus elicited were put to Mr. Summerfield when he was cross-examined. He accepted that the possibility of the sifter being involved was the kind of thing he and Dr. Ketchell had in mind when agreeing to scenario 3. He gave some reasons for thinking it less likely than other potential causes but accepted it as a reasonable possibility. The point being made by the defence, and being accepted by Mr. Summerfield, was that the actual cause was unknown, but here was an illustration of something within scenario 3 which might have happened. If it had, it would explain the explosion in a way which did not involve any of the other dust in the Mill which was allowed to accumulate and to remain in places where it should not have been over a period of time. 23. Having summarised this state of the evidence, the judge then set out part of reexamination of Mr. Summerfield by Mr. Badenoch on behalf of the prosecution. Mr. Badenoch was exploring, for the first time, ways in which it might be shown that one or more of the alleged faults of WTL and Mr. Boden had caused a scenario 3 event. The key passage is this:- Q. What mechanisms can a company have to prevent a plant failure of that kind? A. It’s really down to maintenance and repair. It’s making sure that the kit is in good condition and making sure that it’s properly connected, that the flexible connections are sound and not leaking, and with regard to reconnecting equipment after a period of maintenance, it’s a question of having the procedural controls in place that enable you to check that everything important has actually been reconnected and this is something which goes back a long way in history. We’ve had these sort of incidents before, where people forget to reconnect pieces of equipment and so there are management, safety management control systems in place to actually check that everything has been reconnected that should be reconnected. Q. And does that include, for example, a safe operating procedure for the sifter? A. Yes. Q. Does that include, for example, the proper training of the person who is concerned with the sifter? A. Yes. Q. And does it also include, for example, the proper use of sealants and assessment of them for the purpose of safety? A. Yes, it’s important whenever you are making any repair that the material…. I’m sorry, I’m going too fast. It’s important whenever you’re making a repair on a piece of equipment that the materials you use are specified as being fit for that purpose and that they’re used appropriately. Q. And so is the likelihood of an equipment failure informed by things of that kind? A. It is. 24. The importance of that piece of evidence is that it is the only evidence that the failure of the sifter, if it was the cause, was the result of negligence. It is also the only evidential basis for the proposition that any failure of the kind supposed in scenario 3 must have involved fault in one or more of the ways explained. The sifter was an example of the kind of machine failure which scenario 3 required. It could have happened equally well in one of the many grinders in the Mill, or one of the other sifters. There was evidence that the safety management systems at the Mill were bad, and there were no documented systems for maintaining the machines, or reconnecting them after repair to ensure that this was done safely. There was evidence that maintenance was shoddy and reactive and not systematic. There was no evidence that any of this actually caused a failure of a machine as postulated in scenario 3 on17 July 2015 or even that there actually was such a failure. Scenario 3 was put forward as a possible cause of the explosion. Once accepted as such, it is submitted on behalf of the respondents that the prosecution had to prove that however it occurred, fault must have been involved. 25. The judge then moved to explain her decision. The final passage of her judgment at paragraphs 24-31 is as follows:- 24. In accordance with the Galbraith test I have asked myself whether the prosecution evidence, taken at its highest, is capable of establishing causation to the criminal standard of proof, ie making the jury sure that the defendants’ negligence was at least a more than minimal cause of the explosion and the deaths. As indicated in G&F and Broughton, where the evidence on causation consists in drawing inferences from a variety of circumstances, the jury will only be able to be sure if it can rule out any realistic possibility consistent with innocence. 25. In this case, where the state of the Mill and remaining machinery after the explosion and rescue/recovery operation was such that no firm conclusions could be drawn about the mechanism of the wood dust explosion, the challenge for the prosecution was always going to be to link acts and omissions (principally omissions in this case) on the part of company and Mr Boden to the explosion itself. The prosecution has sought to make this link by using expert evidence to draw a series of educated inferences from the evidence in order to identify possible causes. Whilst the jury have a great deal of evidence going to breaches of health and safety at the Mill generally, the expert evidence is all they have regarding the possible causes of the explosion on the day in question. 26. Pointing to breaches of the various health and safety regulations, which thereby increase the risk of occurrence of a wood dust explosion, may be sufficient for demonstrating the Health and Safety offences. But the very serious offences of corporate manslaughter and gross negligence manslaughter engage the much more exacting requirement of making the jury sure that the (gross) negligence was a cause of the deaths; in this case a cause of the explosion which led to the deaths. 27. In circumstances where the experts could say, with certainty, no more than that it was a wood dust explosion, the prosecution have sought to make the jury sure of the necessary causative link by asking their lead expert to take into account all the evidence in the case, including the evidence of all the other experts, for the purposes of giving an opinion on possible causes of the explosion. Expert input was necessary as there are many and various technical aspects involved in wood dust explosions, such as: the size of dust particles required for suspension in air, the mass of dust combined with size of room, configuration of the room assessing the scope for any venting, and many others. No jury could be expected to make those calculations or assessments on their own, without the assistance of an expert. When that expert input generates a number of realistic (“highly credible”) possible scenarios for the presence of a cloud of explosible dust in the Mill on the morning of17 July 2015 , as happened here, the jury cannot logically be sure of causation unless the prosecution is able to show by evidence that all the possibilities can be attributed, at least in part, to the alleged negligence. In other words, that the jury can exclude any realistic possibility consistent with innocence. 28. Where the Crown has sought to make its case on causation by reference to expert evidence raising and critically examining possible scenarios, and has moreover, specifically instructed its expert to do so taking account of ALL the evidence in the case, it is not open to the jury to reject what the prosecution’s own expert has identified as a realistic possibility. This is not a case where there is any other evidence which the jury could use to test, temper or reject the expert opinion. The matters said by Mr Badenoch to be the premises upon which the Forest Fresh minisifter example was based, and which he said could easily be dismissed by a jury were not raised with the expert, nor were many of them addressed by the factual evidence: there was no evidence of who actually disassembled and re-built the Forest Fresh mini-sifter, what process they used, whether there even were any manufacturer’s instructions, whether the sealant was in fact the wrong type, the list goes on. It seemed at some points in the argument as if Mr Badenoch was approaching this on the basis that it was for the defence to prove that the minisifter example was what in fact happened. But that is not so; the defence needed to do no more than raise a realistic possibility for the source of the dust which exploded. Once their expert has accepted the defence example as a realistic possibility, the Crown is obliged to make the logical causative link by demonstrating that the Forest Fresh minisifter example of Scenario 3 was attributable (at least in part) to negligence on the part of the company/GB. 29. As to this, the “wealth of evidence” referred to by Mr Badenoch amounted to a list of the ways in which the Crown say that WTL and GB breached Health and Safety legislation and regulations over the 6 years between 2009 and 2015. He asked Mr Summerfield to comment, in respect of each alleged failing, on the extent of the gap between what should have been done and what the company did do during that time. Mr Summerfield’s evidence was that, in most cases, the gap was very wide. But the failings upon which Mr Badenoch invited such comment were put in general terms – the absence of a process design, of risk assessments, of written operating procedures, of plotted hazard areas in the mill, to name but a few. The furthest extent of Mr Summerfield’s evidence, as illustrated by the exchange in re-examination set out above, was that these matters were very important in identifying and reducing/controlling risk such that, without them, the risk was very much heightened – “an accident waiting to happen”, as Mr Badenoch put it. But as Mr Antrobus rightly pointed out, this is wrongly to elide risk with causation. Increasing the risk of something happening is not the same as causing it to happen. The fact that the risk of explosion may have been high cannot of itself demonstrate that the particular explosion occurred as a result of the negligence of WTL/GB. It is necessary to go further, to demonstrate how a risk assessment, or a written operating procedure or any other control measure which the prosecution say should have been in place but was not, would have acted to have prevented a breakdown of plant, as contemplated by Scenario 3 in general, or by the Forest Fresh mini-sifter example in particular. What is missing in relation to Scenario 3 is a forensic process linking the (possible) mechanism of dust generation/explosion to the alleged negligence. Mr Badenoch’s approach would require the jury to jump between health and safety failings generally and the specific failure of plant posited by the experts under Scenario 3, without any evidence, in effect to speculate about what a risk assessment might have said/recommended, or how any change of procedure implemented as a consequence of a risk assessment or written operating procedure could have prevented a failure of equipment on the morning of17 July 2015 . 30. I have reflected on one further point arising from Mr Badenoch’s answer to a question which I put to him in argument: did he accept that there were any circumstances under which there could have been a non-negligent explosion at the mill? He said that he did not accept this, that any wood dust explosion, under any circumstances, must have resulted from a negligent failure to observe Health and Safety regulations at the Mill; it could not have happened unless there had been such failings. Clearly this is a circular argument, but it also, to my mind, sets a dangerous precedent in cases like this: if this approach is right then it would be enough for the prosecution in a health and safety manslaughter case to point to breaches of health and safety duties and say that those breaches of themselves are sufficient to demonstrate causation. That would be to reverse the burden to proof, to lay upon the defence the obligation in a health and safety case of showing that the death was not the result of such breaches. 31. It is for these reasons that I am not satisfied that the jury in this case would be able on the evidence to be sure of the causative link between gross negligence on the part of D!/D2 and the explosion causing the deaths. The presence of Scenario 3 as a “highly credible” possible cause, taken together with the absence of evidence addressing the link between breach of duty and a machine failure/rupture on the morning in question, means that the jury would be unable to rule out a possible cause consistent with innocence”