From Mental Health Law Online
A sentence of life imprisonment and conviction for murder was quashed, and substituted with a conviction for manslaughter on the grounds of diminished responsibility and a restricted hospital order; this was even though the appellant had pleaded guilty to murder, as her decision to plead guilty was affected by her medical condition, which also substantially reduced her responsibility for the killing.
The appellant had been found fit to plead in the legal sense (she was of sufficient intellect to comprehend the course of proceedings so as to make a proper defence, to instruct solicitors, to know that she might challenge any jurors to whom she may object, and to comprehend the details of the evidence). However, the medical evidence was that she was unable to plead with understanding to the indictment: if she were able to plead with such understanding she would plead guilty to manslaughter on the basis of diminished responsibility. This plea would have been accepted by the trial judge and was supported by the medical evidence.
Toulson LJ, giving the judgment of the court, agreed with the observation that "psychiatric understanding and the law in relation to mentally ill defendants do not always sit together comfortably". Fresh medical evidence supported a hospital order under s37 and restriction order without limit of time under s41. It made clear that the decision to plead guilty to murder was affected by her medical condition, which also substantially diminished her responsibility for the killing. The murder conviction was therefore unsafe and substituted with a conviction for manslaughter on grounds of diminished responsibility