The investigations into allegations of abuse by UK personnel in Iraq have now closed without any prosecutions brought, according to the Defence Secretary.
In a written statement to the House of Commons on Tuesday, Ben Wallace said the Service Police Legacy Investigations (SPLI) had assessed 1,291 allegations since July 2017 but had now "officially closed its doors".
He said that despite 178 allegations having been formally pursued in 55 separate investigations, no soldiers had been prosecuted as a result of the SPLI work.
According to SPLI reports, five people were referred to the Service Prosecuting Authority in 2019, resulting in no charges.
Mr Wallace said: "The vast majority of the more than 140,000 members of our Armed Forces who served in Iraq did so honourably.
“Many sadly suffered injuries or death, with devastating consequences for them and their families."
The SPLI replaced the Iraq Historic Allegations Team (IHAT) in 2017 after Phil Shiner, a solicitor who had taken numerous cases to IHAT, was struck off for using financial incentives to obtain clients.
Mr Wallace said that while some allegations against British troops "were credible", others were not and the credibility of allegations had been a "significant challenge throughout the investigations".
The Defence Secretary added: "However, not all allegations and claims were spurious, otherwise investigations would not have proceeded beyond initial examination and no claims for compensation would have been paid.
"It is sadly clear, from all the investigations the UK conducted, that some shocking and shameful incidents did happen in Iraq.
"We recognise that there were four convictions of UK military personnel for offences in Iraq including offences of assault and inhuman treatment.
"The Government's position is clear – we deplore and condemn all such incidents."
Three soldiers from the Royal Regiment of Fusiliers were jailed for between 20 weeks and two years by a court martial in February 2005 for abusing Iraqi civilians at a camp near Basra two years earlier.
In 2007, a soldier from the Queen's Lancashire Regiment was jailed for a year in connection with the death of Iraqi civilian Baha Mousa in September 2003.
The Ministry of Defence has paid out a total of more than £20m in compensation settlements for abuse claims from Iraqi nationals.
Mr Wallace added that in some cases investigations "in arduous, battlefield conditions" by the Royal Military Police "did not manage to secure all the required evidence, with the result that opportunities to hold those responsible to account may now have been lost".
He said: "I apologise unreservedly to all those who suffered treatment at the hands of UK forces, which was unacceptable."