AN EX-Royal Marine currently serving life in Erlestone Prison after being found guilty of murdering an injured Afghan fighter has been refused bail pending a new challenge against his conviction.

Sergeant Alexander Blackman, 42, of Taunton, in Somerset, failed to persuade two judges at the Court Martial Appeal Court in London to free him from prison.

The bail move followed the announcement by the Criminal Cases Review Commission (CCRC), the independent body that investigates possible miscarriages of justice, of its decision to refer Blackman's conviction and sentence to the court for review.

Blackman watched today's proceedings via video link from the jail near Devizes.

His wife, Claire, was in the packed courtroom with dozens of supporters.

Blackman was convicted in November 2013 by a court martial in Bulford and sentenced to life with a minimum term of 10 years, which was later reduced to eight years on appeal because of the combat stress he was suffering from at the time of the incident.

He shot the insurgent in Helmand province in 2011 while serving with Plymouth-based 42 Commando.

There was a loud sigh of disappointment from supporters in the public gallery as the decision to refuse bail was announced by Lord Chief Justice Lord Thomas, sitting with Mr Justice Sweeney.

The CCRC referred the case for review following an 11-month "in-depth" investigation.

It announced it had concluded that a number of new issues, including fresh evidence relating to Blackman's mental state, "raise a real possibility" that the Court Martial Appeal Court "will now quash Mr Blackman's murder conviction".

Blackman shot the insurgent, who had been seriously injured in an attack by an Apache helicopter, in the chest at close range with a 9mm pistol before quoting a phrase from Shakespeare as the man convulsed and died in front of him.

Blackman told him: ''There you are. Shuffle off this mortal coil... It's nothing you wouldn't do to us.''

He then turned to comrades and said: ''Obviously this doesn't go anywhere, fellas. I just broke the Geneva Convention.''

The shooting was captured on a camera mounted on the helmet of another Royal Marine.

During his trial, Blackman - who denied murder and was known at that stage as Marine A - said he believed the victim was already dead and he was taking out his anger on a corpse.

He was ''dismissed with disgrace'' from the Royal Marines after serving with distinction for 15 years, including tours of Iraq, Afghanistan and Northern Ireland.

Speaking outside the court following the ruling, Blackman's wife Claire Blackman said: "We are obviously disappointed by the judges' decision not to grant bail this afternoon.

"However we must remember that earlier this month the Criminal Cases Review Commission decided to refer the case back to the Appeal Courts and this is the most important step towards getting Al's conviction and sentence overturned.

"We are grateful to the courts for expediting the appeal process."

Lord Thomas continued reporting restrictions imposed at a hearing last Friday which prevents reporting of the details of the proceedings.

But, he gave the go-ahead for the court's ruling on the bail application and other matters to be publicised.

In the judgment, Lord Thomas said the "practice of the court is always to expedite appeals, rather than release on bail".

He said that "despite the unprecedented nature of this case", the court "can see no basis for departing from what is that practice".

Dealing with the bail application, Lord Thomas said it was the practice of the Court of Appeal Criminal Division and the Court Martial Appeal Court "only to grant bail in exceptional circumstances".

He said Blackman's lawyer, Jonathan Goldberg QC, submitted that "this is an exceptional case, both as to the circumstances of the crime and as to the appellant".

Lord Thomas added: "He emphasises the appellant's otherwise exemplary service, the fact that he was given bail prior to trial, the fact he was allowed to handle weapons while on bail, the strength of his case on appeal, the risk he might have to serve longer in prison than the court orders on the appeal and the exceptional sureties that have agreed to stand for him.

"He also emphasises the appellant has been a model prisoner, that he has a job to go to and that his wife can be relied on to exert control over him. He would bear with fortitude a return to prison."

The prosecution did not object to unconditional bail.

Lord Thomas said the court "recognises that the prosecution of the appellant for murder and his subsequent conviction for murder were unprecedented".

He announced: "Despite the powerful new psychiatric and other evidence, the question of whether a verdict of diminished responsibility should be substituted or a retrial ordered is a matter of dispute on the part of the Crown.

"In those circumstances the court cannot say that the merits of the appeal are overwhelming, nor can it say that there is any other basis upon which it could take the exceptional course of allowing bail in circumstances where it is able so substantially to expedite the appeal."

Blackman's conviction challenge involves a number of grounds - including a submission that the murder conviction "should be quashed and a conviction for manslaughter by reason of diminished responsibility should be substituted, or a retrial ordered".

An appeal hearing is now expected to be held either at the end of January or "as early as possible" in February to deal with the issue of diminished responsibility.

Lord Thomas said: "It seems to us that the interests of justice are best served in this case by ordering that the appeal on the issue of whether the conviction for murder should be quashed and a verdict of manslaughter either substituted or a fresh trial be ordered on that basis should be heard first, leaving to one side the other grounds of the appeal pending the court's determination on that point."