The Court of Criminal Appeal has quashed Cecil Tomkins’s murder conviction and ordered a retrial, ruling that the jury was not properly directed on diminished responsibility.
In a judgment delivered on 16 October 2012, the court said the trial judge should have explained that evidence of premeditation does not necessarily conflict with a finding of diminished responsibility. The omission was, in the appeal court’s view, substantial and fundamental to the fairness of the trial and was reasonably likely to have left the jury with an incomplete understanding of the law.
Tomkins had been convicted by a Central Criminal Court jury in March 2012 of murdering his brother, Walter Tomkins, at their family home in Cronelea, Shillelagh, County Wicklow, on 1 July 2010. He appealed on several grounds, including that the verdict was perverse and that the jury had not been properly instructed on the available defences.
The appeal court rejected challenges concerning accident, insanity, intent and provocation. It said there was no evidence the shooting was accidental; the defence accepted there was insufficient evidence to establish insanity; and the jury had evidence on which it could find the required intent and reject provocation. On those issues, the court did not consider the verdict perverse.
The diminished-responsibility issue arose from evidence that Tomkins had Parkinson’s syndrome and dementia, with damage affecting his frontal lobes. Defence medical evidence said he had a mental disorder at the time and that it probably impaired his judgment and emotional regulation. The appeal court noted that the prosecution had not called medical evidence contradicting that opinion on diminished responsibility, but also said a jury is not bound to accept unchallenged medical evidence where there is a rational basis to reject it.
The trial judge recited the statutory test and summarised the medical evidence. But the prosecution had relied on the steps Tomkins took before the shooting as evidence of premeditation, particularly in contesting provocation. The appeal court held that the jury also needed a clear direction that premeditation did not, by itself, necessarily defeat diminished responsibility.
The appeal judges stressed that they were not substituting their view for the jury’s or finding that diminished responsibility had been proved. They quashed the conviction because of the omission in the jury direction and directed a retrial.