A ROYAL Marine found guilty of murdering an injured Afghan fighter has lost a bid to take his battle to overturn his conviction to the UK's highest court.

Three leading judges refused to give Sergeant Alexander Blackman permission to appeal to the Supreme Court.

Earlier this year, Blackman's appeal against conviction was rejected by Lord Chief Justice Lord Thomas, Sir Brian Leveson and Lady Justice Hallett at the Court Martial Appeal Court in London. Lady Justice Hallett, sitting at the same court yesterday, announced their decision to refuse his application to continue his fight at the Supreme Court.

After being convicted last November at a court martial in Bulford, Wiltshire, Blackman was sentenced to life with a minimum term of 10 years. He was also "dismissed with disgrace" from the Royal Marines after he had served with distinction for 15 years, including tours of Iraq, Afghanistan and Northern Ireland.

Although his conviction appeal was dismissed in May, the three judges allowed his sentence challenge, reducing the 10-year minimum to eight years, the least he must serve before he can be considered for parole.

The reduction was made because of the combat stress disorder he was suffering at the time of the incident.