A "rogue" SAS unit is said to have carried out night missions during which they executed civilians in Afghanistan villages, newly-released court documents claim.

The files had previously been withheld from an ongoing High Court legal case by the government after an Afghani man claimed he was unlawfully detained and mistreated.

Communications from within high ranks of the special forces reveal huge concern for the killings of over 33 Afghan people in 11 different night raids on homes by the same unit.

The documents, reported by The Sunday Times Insight team, expose one significant incident that has been alleged to be a quadruple murder by UK troops, and is now at the centre of the case.

The alleged killings are reported to have been carried out by a "rogue" SAS unit

On February 16, 2011, the unnamed SAS unit arrived at the village of Gawahargin in southern Helmand province.

Documents claim they raided a man's home as he was suspected of being a member of a gang that was planting roadside bombs, with family members including his 19-year-old brother Saifullah stepping out into the night with their hands up.

They add women and children were tied up, with black hoods placed on their heads as they were detained in one part of the compound, then heard gunfire.

After the special forces soldiers left, Saifullah went back into the house and found his dad, brothers and cousin dead with several bullet holes in their heads, it is alleged.

The unit raided a man's home as he was suspected of being a member of a gang that was planting roadside bombs

As part of the litigation, the allegation about the four civilian killings was passed on to the special investigation branch of the Royal Military Police (RMP), who felt the claims were sufficiently serious to launch an investigation in March 2014.

In one note written on the day of the killings, an officer said he had a "very difficult" meeting with the colonel in charge of an Afghan partner unit (APU) about the incident.

The colonel brought along nine of his soldiers, one of whom was a relative of Saifullah’s family and who gave assurances that the dead men were teachers and farmers, not Taliban supporters.

The colonel said his soldiers had reported that nobody had fired at the coalition forces, but the men "were shot anyway".

An Afghan partner unit claimed the locals were not Taliban supporters

The officer's note added: "He suggests that two men were shot trying to run away, and that the other two men were 'assassinated' on target after they had already been detained and searched."

There is also concern that of the 33 deaths, 10 were near-identical in their circumstance, where a captured male family member is back at his empty home to clear the way for a search of the premises, only to get their hands on a weapon and attack the soldiers in "clearly impossible odds".

In response to the Sunday Times' story, the Ministry of Defence said: "This is not new evidence, and this historical case has already been independently investigated by the Royal Military Police as part of Operation Northmoor. It has also been subject to four reviews conducted by an independent review team.

"These documents were considered as part of the independent investigations, which concluded there was insufficient evidence to refer the case for prosecution. The Service Police and the Service Prosecuting Authority of course remain open to considering allegations should new evidence, intelligence or information come to light."