In R v Broughton  EWCA Crim 1093, the appellant appealed to the Court of Appeal against his conviction for gross negligence manslaughter. His appeal centred around the necessary proof required for causation in gross negligence manslaughter.
In summary, the appellant had supplied his girlfriend, the victim, with Class A drugs at a music festival. The victim experienced a bad reaction to the drugs – the evidence demonstrated that the appellant has ‘bumped up’ the drugs. The case for the prosecution at trial was that the appellant had supplied the drugs to the victim and had remained with her throughout. As a result of this, the appellant owed a duty of care to seek and secure medical assistance for the victim; his failure to do so amounted to a breach of that duty and was a substantial cause of her death. The expert witness at trial testified that the victim was ‘seriously unwell and in need of urgent medical care’ and she stood a 90% chance of survival with medical intervention. On this evidence, the defence made a submission of no case to answer on the basis that the evidence, taken at its highest, could not establish causation to the criminal standard. The judge rejected this submission and the defendant was convicted before a jury.
On appeal, the appellant contended that the trial judge had used the wrong test to establish whether causation was satisfied to the criminal standard and, in any event, there was insufficient evidence to meet that standard. In particular, according to the appellant, the prosecution had to prove, beyond reasonable doubt, that the victim would have lived (ie the medical intervention would have saved her life).
The appeal against conviction was upheld. The Court of Appeal, led by Lord Burnett CJ, confirmed the correct test to be that there was a serious and obvious risk of death and that medical assistance would have saved the victim’s life. More specifically, the prosecution had to establish the specific point in time when the victim’s condition reached the threshold of involving a serious and obvious risk of death and the prospects of survival at that point. The prosecution had not fixed on a time at which it was contended that the deceased’s condition posed an obvious and serious risk of death. Given the 90% chance of survival, according to the expert witness, the prosecution were unable to prove that there remained a serious and obvious risk of death at the time the victim’s condition deteriorated. As such, the conviction was unsafe and quashed.
Broughton is an important judgment in three respects:
First, it confirms that the test to be applied in causation cases is whether the victim would have lived with timely medical assistance. At trial, the prosecution had submitted that it was sufficient to prove that the victim was deprived of a ‘significant and substantial chance of survival’. This was not enough, according to the Court of Appeal. The question to ask is whether the medical assistance would have saved her life.
Second, Broughton confirms the approach adopted in the earlier case of Gian v Crown Prosecution Service  EWCA Crim 2553 that ‘in many homicide cases, determining the cause or causes of death did not rely exclusively on expert opinion but could be collected from surrounding circumstances’ (per Lord Burnett CJ in Broughton at ). This simply means that juries are required to consider expert evidence in the context of all other relevant evidence and make judgements based upon realistic and not fanciful possibilities.
Finally, it provides a relatively clear statement as to the standard that must be met by the prosecution in terms of proof of causation. The prosecution must establish a point in time when they allege the serious and obvious risk of death arose, that there was a realistic chance of survival with medical treatment at that time, and that the defendant failed reasonably to secure medical treatment at that time. The prosecution’s inability to do so meant that causation, to the criminal standard, was not proven.