Former Archbishop of Canterbury Lord Carey of Clifton is praying for the release of jailed 'Marine A' whose murder conviction has been overturned.
George Carey joined MPs, peers and retired military chiefs in calling on judges to grant mercy to Sergeant Alexander Blackman in court on Tuesday.
The marine's new prison sentence for shooting a wounded Taliban is being decided by the Appeal Court after it reversed his murder conviction, downgrading it to manslaughter because of combat stress.
Lord Carey, 81, described Sergeant Blackman as a 'magnificient soldier' with a 'long and distinguished record of service' to the Queen.
'I have served myself in the armed forces and know that in the heat and dust of battle, split second decisions must be made and expediency can sometimes overcome strict morality even for the best of men,' he said in a public statement on Sunday.
'Unless you have walked a mile in their shoes it is hard to understand the pressures,' he added.
'The long prison sentence he has already served seems long enough both for him and his dignified wife, and I pray for his release. We need men like this at this time.'
The former Church leader's intervention comes Blackman's wife Claire and Conservative MPs spearheaded a campaign for his release.
Richard Drax, South Dorset MP and ex-Army officer, said five judges had it in their power to show him mercy on Tuesday.
'Let's not forget that this insurgent was no different to the terrorist who caused carnage on Westminster Bridge on Wednesday, before fatally stabbing PC Keith Palmer,' he said on Sunday.
'Warped and twisted hatred drives them to commit crimes we simply cannot comprehend, and the only people who stand between them and us are brave men like PC Palmer and Mr Blackman.'
He wrote on his website: 'What on earth would it achieve by keeping Mr Blackman in jail? This former Royal Marine has spent nearly three and half years in prison already.
'He has paid a terrible price for serving his country, to the point where something inside him just snapped.
'We owe him a debt of gratitude and I sincerely hope and pray this will be sensibly reflected by our top judges on Tuesday morning.'
Blackman was sentenced to life in prison with a minimum of 10 years in 2013 after he was filmed shooting a fatally wounded Taliban insurgent. But his sentence of murder was downgraded to manslaughter on with psychologists ruling he was suffering from combat stress disorder.
The Court of Appeal is deciding his new prison sentence.
