Blackman, R. v

For diminished responsibility under the Homicide Act 1957, impairment is substantial when it is important, weighty, significant and appreciable. It is not enough that the impairment is more than trivial. Agreed psychiatric evidence is highly influential but does not decide the issue. The tribunal must assess it with the whole of the evidence and may reject it only on a rational basis.

On an appeal supported by fresh psychiatric evidence, the appellate court must decide for itself whether the conviction is safe. It may substitute manslaughter by reason of diminished responsibility where the evidence establishes the partial defence on the balance of probabilities, even though that evidence was not before the trial tribunal.

In 2013 the appellant was convicted by a court martial of murdering a wounded insurgent in Afghanistan and was sentenced to life imprisonment. No psychiatric evidence had been obtained before conviction. An earlier appeal against conviction was dismissed, although the minimum term was reduced on the sentence appeal: R v Blackman [2014] EWCA Crim 1029; [2015] 1 WLR 1900.

The Criminal Cases Review Commission referred the case after fresh psychiatric evidence indicated that the appellant had an adjustment disorder at the time of the killing and trial. The prosecution did not challenge that diagnosis. The central issues were whether the fresh evidence made the murder conviction unsafe and, if so, whether manslaughter by reason of diminished responsibility should be substituted rather than a retrial ordered.

1. Appeal allowed. The court quashed the murder conviction and substituted manslaughter by reason of diminished responsibility. Sentence was adjourned for submissions.

2. Section 2 of the Homicide Act 1957, as amended, governed the partial defence. Applying R v Golds [2016] UKSC 61, substantial impairment meant impairment which was important or weighty. The court accepted that an adjustment disorder was a recognised medical condition capable of producing the required abnormality of mental functioning.

3. The unanimous psychiatric evidence did not itself determine the issue. The court had to assess all the evidence, including the video footage, the appellant’s prior conduct, the stressors of his deployment and the evidence bearing on his mental state. However, there was no rational basis to reject the experts’ conclusion that the disorder substantially impaired his ability to form a rational judgment and exercise self-control.

4. The failure to advance diminished responsibility at trial was not a tactical choice. The fresh evidence would have required the defence to be left to the Board and could have affected its verdict. Applying the fresh-evidence approach stated in Burridge [2010] EWCA Crim 2847, the court concluded that the murder verdict was unsafe.

5. On the balance of probabilities, the adjustment disorder significantly contributed to the killing. The appellant’s conduct before deployment had been exemplary. Exceptional operational stress, grief, isolation, exhaustion and threat had impaired his judgment and self-control. His efforts to conceal the shooting showed some planning, but did not demonstrate an unimpaired capacity to apply the Armed Forces’ moral standards or to evaluate the consequences of his actions. The statutory conditions were therefore established.

• Court Martial Appeal Court: On the Criminal Cases Review Commission reference, allowed the appeal, quashed the murder conviction and substituted manslaughter by reason of diminished responsibility: [2017] EWCA Crim 190.
• Court Martial Appeal Court: Dismissed the earlier appeal against conviction but allowed the sentence appeal and reduced the minimum term from 10 to 8 years: [2014] EWCA Crim 1029; [2015] 1 WLR 1900.
• Court martial at Bulford: In 2013 convicted the appellant of murder and imposed life imprisonment with a minimum term of 10 years.