A “rogue” Special Air Service (SAS) unit is suspected of executing unarmed civilians in Afghanistan and fabricating reports to cover up potential war crimes, according to reports.

Special forces soldiers allegedly murdered Afghans during raids on their homes and then planted guns at the scene to make it appear as though they had been Taliban insurgents.

Some of the victims were handcuffed and hooded before being shot dead, Royal Military Police (RMP) sources told the Sunday Times.

Many of the alleged assassinations relate to a campaign of night raids designed to bring down the Taliban by capturing their leaders and taking them to detention centres for interrogation.

British Army officers speaking to the Times claimed some SAS soldiers adopted a “shoot-to-kill” policy during the missions, which were often said to rely on flawed intelligence.

“Credible and extremely serious” evidence about the potential scandal has been gathered by Operation Northmoor, a classified RMP investigation based in an underground bunker in Cornwall.

The initial inquiry, which was investigating unlawful killings between 2010-2013, and offences including false imprisonment and assault, was expected to run until 2021.

However, the Ministry of Defence recently told RMP officers to finish most of their work by this summer.

Yemen's prime minister accuses UK of war crimes

Detectives had been looking into 52 alleged killings, but are now investigating just one incident which involved four family members being shot dead during a night raid in Helmand province in 2011.

A military police source told the Times that the MoD wanted to “avoid any of the detail of the accusations getting into the press and thereby undermining, in their view, national security, public trust, [and] work with allies”.

Afghanistan: Between Hope and Fear Show all 16 1 /16 Afghanistan: Between Hope and Fear Afghanistan: Between Hope and Fear 2001 Afghans at the Killi Faizo refugee camp desperately reach for bags of rice being handed out to the thousands who escaped the bombardment in southern Afghanistan during Operation Enduring Freedom. (Chaman, Pakistan, December 4, 2001) Paula Bronstein Afghanistan: Between Hope and Fear 2002 Mahbooba stands against a bullet-ridden wall, waiting to be seen at a medical clinic. The seven-year-old girl suffers from leishmaniasis, a parasitical infection. (Kabul, March 1, 2002) All photos Paula Bronstein Afghanistan: Between Hope and Fear 2003 A mother and her two children look out from their cave dwelling. Many families who, fleeing the Taliban, took refuge inside caves adjacent to Bamiyan’s destroyed ancient Buddha statues now have nowhere else to live. (Bamiyan, November 19, 2003) Paula Bronstein Afghanistan: Between Hope and Fear 2007 Students recite prayers in a makeshift outdoor classroom in the Wakhan Corridor, a mountainous region in northeastern Afghanistan that extends to China and separates Tajikistan from India and Pakistan. (Northeastern Afghanistan, September 2, 2007) Paula Bronstein Afghanistan: Between Hope and Fear 2007 Bodybuilders in the 55-60 kg category square off during a regional bodybuilding competition. Many Afghan men, like others around the world, feel that a macho image of physical strength is important. (Kabul, August 6, 2007) Paula Bronstein Afghanistan: Between Hope and Fear 2008 A woman in a white burqa enjoys an afternoon with her family feeding the white pigeons at the Blue Mosque. (Mazar-e-Sharif, March 8, 2008) Paula Bronstein Afghanistan: Between Hope and Fear 2009 Addicts inject heroin while trying to keep warm inside the abandoned Russian Cultural Center, which the capital city’s addicts use as a common gathering point. Heroin is readily available, costing about one dollar a hit. (Kabul, February 9, 2009) Paula Bronstein Afghanistan: Between Hope and Fear 2009 An elderly man holds his granddaughter in their tent at a refugee camp after they were forced to flee their village, which US and NATO forces had bombed because, they claimed, it was a Taliban hideout. (Surobi, Nangarhar Province, February 7, 2009) Paula Bronstein Afghanistan: Between Hope and Fear 2009 Seven-year-old Attiullah, a patient at Mirwais Hospital, stands alongside an X ray showing the bullet that entered his back, nearly killing him. Attiullah was shot by US forces when he was caught in a crossfire as he was herding sheep. (Kandahar, October 13, 2009). Paula Bronstein Afghanistan: Between Hope and Fear 2010 US Army Sargeant Jay Kenney (right), with Task Force Destiny, helps wounded Afghan National Army soldiers exit a Blackhawk helicopter after they have been rescued in an air mission. (Kandahar, December 12, 2010) Paula Bronstein Afghanistan: Between Hope and Fear 2010 An Afghan National Army battalion marches back to barracks at the Kabul Military Training Center. (Kabul, October 4, 2010) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Eid Muhammad, seventy, lives in a house with a view overlooking the hills of Kabul. He and millions of other Afghans occupy land and housing without possessing formal deeds to them. (Kabul, November 21, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Razima holds her two-year-old son, Malik, while waiting for medical attention at the Boost Hospital emergency room. (Lashkar Gah, Helmand Province, June 23, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Young women cheer as they attend a rally for the Afghan presidential candidate Ashraf Ghani. (Kabul, April 1, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2014 Burqa-clad women wait to vote after a polling station runs out of ballots. (Kabul, April 5, 2014) Paula Bronstein Afghanistan: Between Hope and Fear 2015 Relatives, friends, and women’s rights activists grieve at the home of Farkhunda Malikzada, who was killed by a mob in the center of Kabul. Farkhunda was violently beaten and set on fire after a local cleric accused her of burning a Qur’an. (Kabul, March 22, 2015) Paula Bronstein

Drone footage gathered by Operation Northmoor reportedly shows soldiers in British uniform opening fire, contradicting claims that the British army’s Afghan partners, who acted as backup and interpreters, were responsible for shooting civilians.

It is alleged that SAS operatives doctored mission reports to pin the blame for the killings on their Afghan partners, so the incidents wouldn’t be passed onto regular army command and investigated.

Bullets recovered from civilians’ bodies also matched the 5.56mm calibre used by the SAS, rather than the larger bullets used by Afghan special forces.

An unnamed source told the Times: “It says [in the after-action reports] only the Afghan partners fired... he’s dressed in British military equipment, and the guy was shot and killed with a 5.56.”

There have been further allegations that SAS soldiers planted Russian Makarov pistols on victims' bodies and then took photos of the corpse as evidence that they had killed armed Taliban insurgents in self defence.

A spokesperson for the MoD said the RMP had decided to discontinue more than 90 per cent of the 675 cases it started, adding: “The Royal Military Police has found no evidence of criminal behaviour by the armed forces in Afghanistan.”