Anderson v Her Majesty’s Attorney General for the Isle of Man (Isle of Man)

A partial defence of diminished responsibility requires proof of a mental abnormality, a legally recognised cause, and substantial impairment of mental responsibility at the time of killing.

An expert witness may give an opinion on substantial impairment. The ultimate decision remains for the jury, which is not bound by expert evidence.

Where an expert misunderstands this division of functions, counsel should correct the misunderstanding and the trial judge should provide appropriate clarification. A conviction is unsafe where such errors, together with misleading advocacy or uncorrected directions, create a clear possibility of a different verdict.

The appellant admitted killing Neil Roberts on the Isle of Man but relied at trial on self-defence, provocation and diminished responsibility. He was convicted of murder and sentenced to life imprisonment with a minimum term of 15 years.

The High Court of Justice of the Isle of Man, Staff of Government Division, dismissed his appeal against conviction on 25 October 2016 and refused permission to appeal to the Privy Council on 28 February 2019. The Privy Council granted permission on two grounds: whether defence counsel mishandled the psychiatric and psychological evidence concerning substantial impairment, and whether the trial judge misdirected the jury on diminished responsibility.

Appeal allowed. The murder conviction was quashed and a retrial ordered.

1. Diminished responsibility. Under section 22A of the Criminal Code 1872, the defence required proof of an abnormality of mind, arising from a specified cause, which substantially impaired the appellant’s mental responsibility for the killing. The first two elements were not in issue. The burden of proving the defence rested on the appellant.
2. Expert evidence. The authorities, including R v Golds [2016] UKSC 61 and R v Stockwell (1993) 97 Cr App R 260, established that an expert may express an opinion on the ultimate issue of substantial impairment. The jury remains the decision-maker and must not be treated as bound by that opinion.
3. Errors at trial. Dr Puri had misunderstood that he could give his opinion. Nothing indicated that he had withdrawn the conclusion in his report that the appellant’s responsibility was substantially impaired. Defence counsel should have clarified the position and could have drawn attention to the admissible report under section 16 of the Criminal Justice Act 1991. The trial judge should have corrected the misunderstanding and should not have refused recall on the erroneous basis that Dr Puri had deliberately declined to answer. Dr Bradley was never asked the critical question.
4. Safety of the conviction. Applying the approach in Teeluck v State of Trinidad and Tobago [2005] UKPC 14, the issue was the effect of the errors on the trial and verdict, not a general grading of counsel’s competence. The prosecution’s closing speech and the summing-up left the jury with the misleading impression that neither defence expert supported substantial impairment. There was a clear possibility of a manslaughter verdict, so the conviction was unsafe and unsatisfactory under section 33(1) of the Criminal Jurisdiction Act 1993.
5. Remedy. A retrial was appropriate because it was uncertain whether a properly directed jury would return a verdict of manslaughter on diminished responsibility or murder.

1. Privy Council — Appeal allowed on 19 July 2021. The murder conviction was quashed and the appellant was ordered to be retried: [2021] UKPC 20.
2. High Court of Justice of the Isle of Man, Staff of Government Division — Appeal against conviction dismissed on 25 October 2016. Permission to appeal to the Privy Council was refused on 28 February 2019.
3. Court of General Gaol Delivery, Douglas — The appellant was convicted of murder on 17 April 2015 and sentenced on 24 April 2015 to life imprisonment with a minimum term of 15 years.