Blackman is currently serving a life sentence for the 2011 battlefield execution, which was caught on camera. His second appeal began Tuesday and is expected to run for three days.
The first day saw Blackman’s wife and a number of veterans fill the court.
This included a number of retired senior officers up to the rank of general.
“This was a superb soldier. He had been described so in report after report,” Blackman’s lawyer Jonathan Goldberg told the panel of judges.
“The doctors are saying that if a man like that behaves in a way like this, you have to wonder if something wrong was going on in his head, and here the evidence indicates it was.”
The court also heard that the combat stress Blackman endured after a particularly brutal tour may have left him unsure whether the Afghan he shot was still alive.
This claim appears to conflict with Blackman’s own words at the time of the 2011 killing.
He told the victim, who convulsed as he was shot, to “shuffle off this mortal coil, you c*nt” before turning to his men and urging them to be silent because he had “just broken the Geneva Convention.”
The court heard that Blackman had suffered from adjustment disorder, a condition similar in some ways to post-traumatic stress.
Neil Greenberg, a King’s College psychiatrist and professor, who has worked in Afghanistan, told the court that Blackman may have concealed his condition.
“It is fair to say that everybody has their breaking point. There is no such thing as a Rambo type, an Arnold Schwarzenegger soldier, who can face all sorts of stresses and appear to be invulnerable.
“That sort of person only exists in the cinema,” Greenberg said.
At his first appeal, Blackman’s sentence was reduced from a minimum of 10 years to a minimum of eight on the basis of combat stress.
The appeal continues.