Leaked documents accuse the British government and the army of covering up the killing of children and the torture of civilians in Afghanistan and Iraq, according to a Panorama/Sunday Times investigation.
The accusations have been made after new evidence obtained from the Iraq historic allegations team (IHAT), which investigated war crimes carried out by British soldiers in Iraq, and Operation Northmoor, which examined war crimes in Afghanistan.
Detectives from IHAT found evidence of abuse at the British army base in Basra, Camp Stephen, after British soldiers and army staff gave statements detailing that two men were tortured and found dead with bags tied over their heads.
Despite this, British military prosecutors ruled that no soldier would be prosecuted over the incident.
In 2017 IHAT and Operation Northmoor were shut down by the government after a solicitor working on the investigations was fired following accusations he paid people in Iraq to find clients.
Former IHAT and Operation Northmoor investigators have said that Phil Shiner's actions were used as an excuse to shut down investigations – no case IHAT or Operation Northmoor pursued led to a prosecution.
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The Ministry of Defence had no intention of prosecuting any soldier of whatever rank he was unless it was absolutely necessary, and they couldn't wriggle their way out of it
a detective working for IHAT told Panorama.
Eleven British detectives told the Panorama/Sunday Times that they had found credible evidence of war crimes. The year-long investigation revealed murders carried out by an SAS soldier, deaths in custody, beatings, torture and sexual abuse.
The Ministry of Defence has denied the allegations: "Allegations that the MoD interfered with investigations or prosecution decisions relating to the conduct of UK forces in Iraq and Afghanistan are untrue," adding that the cases were referred to the independent Service Prosecuting Authority (SPA.)
The UK's legal programme director for human rights watchdog Amnesty International said: "Reports of killings and torture by British troops in Afghanistan and Iraq, and a subsequent cover up, are deeply troubling."
"If true, those responsible for sanctioning and carrying out torture and other war crimes, at all levels, must be held accountable and where appropriate, prosecuted."
The International Criminal Court (ICC) said it had taken the accusations seriously and would consider an investigation into the British military. If an investigation does go ahead it would be the first of its kind against UK nationals for war crimes.