A German human rights organisation and a British firm have presented a dossier to the International Criminal Court in The Hague containing accusations of over 1,000 incidences of torture by UK forces against Iraqi civilians, and 200 cases of unlawful killing.
The 250-page dossier on war crimes allegedly committed by UK forces in Iraq is the most detailed yet submitted to the ICC's Office. It contains details of beatings, electrocutions, mock executions and sexual assault.
The German-based European Centre for Constitutional Rights and British-based Public Interest Lawyers (PIL) will present their case in London on Tuesday.
Phil Shiner, a solicitor from PIL, told Sky News: "This is historic. The UK has never been investigated by the ICC. There is clear evidence this goes right to the top."
Several top British officials face serious scrutiny, according to Shiner. "I think we easily meet the threshold for these issues to be looked at, I would be gobsmacked and bitterly disappointed if they don't look at this," he told the Independent on Sunday.
The document, "The Responsibility of UK Officials for War Crimes Involving Systematic Detainee Abuse in Iraq from 2003-2008", contains information on more than 400 Iraqis, representing "thousands of allegations of mistreatment amounting to war crimes of torture or cruel, inhuman or degrading treatment".
Accounts from hundreds of Iraqis who claim they were tortured by British soldiers are being considered by the International Criminal Court in The Hague.
One Iraqi detainee said: "The soldier put his boot on my chest and pulled my trousers down.... I was shouting and was curled up against the wall. Then the soldier pulled me by my legs away from the wall. He turned me over on my stomach. He started rubbing his penis on my back, while the other soldiers watched. Then I felt him ejaculate on my back. I was trying to move away but another soldier came and pressed his foot on my legs."
There are also claims regarding the widespread use of "hooding", forcing people to remain in painful "stress positions", sleep deprivation, noise bombardment and deprivation of food and water.
These interrogation methods were previously used by British soldiers in Northern Ireland before being banned in 1972.
A Ministry of Defence spokesperson said: "These matters are either under thorough investigation or have been dealt with ... further action through the ICC is unnecessary when the issues and allegations are already known to the UK Government, action is in hand and the UK courts have already issued judgments.
"We reject the suggestion the UK's armed forces – who operate in line with domestic and international law – have systematically tortured detainees."