An anaesthetist failed to notice during an operation that the anaesthetic tube had become disconnected and the patient suffered a cardiac arrest and died. The trial judge directed that manslaughter was appropriate if gross negligence had been proved. The jury convicted and he appealed, saying that the judge had told the jury to apply the test of gross negligence when he should have applied the test for manslaughter. The CA and HL upheld the court’s decision, since involuntary manslaughter occurs where the defendant had a duty of care to the victim, that he breached it, and that the breach caused death, that he was properly convicted of manslaughter. No state of mind was necessary for conviction of involuntary manslaughter where gross negligence was involved.