The Supreme Court dismissed Joseph Heffernan’s appeal in a judgment addressing the burden of proof for the defence of diminished responsibility in murder cases.
Mr Justice Peter Charleton delivered a concurring judgment on 7 February 2017, agreeing with the principal judgment of Ms Justice O’Malley. He said the Criminal Law (Insanity) Act 2006 requires the accused to establish that a mental disorder substantially diminished their responsibility for the act. The disorder must be an illness, disability, dementia or disease of the mind; intoxication is excluded.
The judgment distinguished diminished responsibility from insanity. Insanity can result in a special verdict of not guilty by reason of insanity, while diminished responsibility reduces murder to manslaughter, with sentence left to the trial judge’s discretion. Charleton J said both defences place a persuasive burden on the accused, who must clearly demonstrate that the relevant defence applies.
He contrasted that requirement with the usual approach to criminal defences: once a defence is raised on a credible basis, the prosecution generally must disprove it beyond reasonable doubt. In his view, the statutory wording for diminished responsibility assigns the burden to the defence. He said an accused relying on it should set out the nature of the mental illness and how it affected their understanding or control in the circumstances of the killing.
In discussing the appeal, Charleton J noted that psychiatric evidence was available to the accused, but the defence had chosen not to call it and instead relied on testing the prosecution’s evidence. The judgment did not state the underlying killing’s circumstances or set out the appeal’s other grounds in this separate concurring opinion.
Charleton J concluded that no general theory about the allocation of proof between prosecution and defence necessarily produces a fair or just result in every case. He supported dismissing the appeal. The judgment identifies the Supreme Court appeal as 2016 No 3 and the Court of Appeal record as 2013 No 165.