R v Sergeant Alexander Blackman (Marine A)
[2017] EWCA Crim 190
Ratio Decidendi
The defence of diminished responsibility applies in military law as it does in civilian law. Evidence of combat stress and adjustment disorder may reduce murder to manslaughter where it substantially impairs responsibility.
Facts
Sergeant Blackman, a Royal Marine, shot and killed a wounded Taliban insurgent in Afghanistan in 2011. He was convicted of murder by court martial. Fresh psychiatric evidence later emerged suggesting he was suffering from an adjustment disorder due to the exceptional pressures of combat.
Judgment Summary
The Court of Appeal allowed the appeal, substituting a conviction for manslaughter on the ground of diminished responsibility. The psychiatric evidence established that Blackman's mental functioning was substantially impaired at the time by an abnormality arising from combat stress.
Key Quotes
"We are satisfied that at the time of the killing, Sgt Blackman was suffering from an abnormality of mental functioning which arose from a recognised medical condition... and that abnormality substantially impaired his ability to exercise self-control."
— Lord Thomas CJ
Subsequent Treatment
Important precedent on the application of diminished responsibility in military contexts.