The wife of a former Royal Marine from Taunton found guilty of murdering a Taliban fighter is submitting a bid to the Criminal Cases Review Commission to have his case referred back to the Court of Appeal.

Psychiatrists claim Alexander Blackman was suffering from a 'recognised mental illness' at the time that went undiagnosed.

Alexander Blackman was jailed for life in 2013 after being convicted of shooting the wounded Afghan captive in the chest at close range in Helmand province two years before.

He had been serving with Plymouth-based 42 Commando in September 2011, when he came across the Afghan insurgent, who had been injured in an attack by an Apache helicopter.

He denied murder, claiming he thought the victim was already dead. His wife, Claire Blackman says he regrets the "instant loss of control" and "poor lack of judgement".

Mr Blackman's prison sentence was later reduced to eight years on appeal, to reflect the combat stress disorder he had been diagnosed with. But his legal team want the murder verdict to be quashed or at least reduced to manslaughter.

New evidence from psychiatrists has revealed that he was suffering from 'recognised mental illness'at the time that went undiagnosed. Mrs Blackman says they undertook extensive research.

Mrs Blackman hopes the Criminal Cases Review Commission, an independent organisation which investigates alleged miscarriages of justice, will take on board her argument and that of their legal team and get the case referred back to the Court of Appeal.