判决理由
For the partial defence of diminished responsibility under s 52 Coroners and Justice Act 2009, 'substantial' impairment means an impairment that is more than merely trivial — it need not be total but it must be significant or appreciable.
事实
The defendant killed his partner. He raised the partial defence of diminished responsibility, relying on a personality disorder.
判决摘要
The Supreme Court held that 'substantial' means something between trivial and total. In most cases, no direction is needed on the meaning of substantial, but where there is an issue, the judge should direct that it means more than merely trivial.
关键引述
"Substantial does not mean total, but it means more than merely trivial or minimal."
— Lord Hughes
后续处理
The leading authority on the meaning of 'substantial' in the diminished responsibility defence.