Some Iraq War veterans may face prosecutions for war crimes after a probe into allegations of torture and unlawful killing, the Press Association reports.
The government-backed criminal investigation unit, the Iraq Historic Allegations Team (Ihat), has been investigating murder, abuse and torture claims related to the war in Iraq since British troops were pulled out in 2009.
Mark Warwick, the former police detective in charge of Ihat, told the Independent there was "significant evidence to be obtained to put a strong case before the Service Prosecuting Authority to prosecute and charge."
Warwick went on to cast doubt over Ihat's intended completion date of 2019, when all investigations are supposed to be finished.
"Over the next 12 to 18 months, we will review all the caseload to better understand the picture and then I think we can say whether 2019 seems realistic," he said.
"There are serious allegations that we are investigating across the whole range of Ihat investigations, which incorporates homicide, where I feel there is significant evidence to be obtained to put a strong case before the Service Prosecuting Authority to prosecute and charge."
As of September 2015, the team had already assessed the cases of 1,515 alleged victims, 280 of whom may have been unlawfully killed. So far only 25 of those cases have been investigated and more than 200 have yet to be opened, The Independent reports.
Of 1,235 reported cases alleging mistreatment, which includes rape and torture, only 45 have been seen to.
Warwick said not all allegations will lead to an investigation.
"What's the likely outcome to be if we do a full investigation, and what's the likely penalty if we convict someone?" he said.
"We would look at the credibility of the allegation in the first instance; and, when we've looked at a lot of these extra cases coming to us, some of them are duplicates of cases, some of them we've already identified as part of our own investigation process, and some are multiple allegations, where we would investigate as a single allegation.
"There are lots of significant cases that we are investigating and at the appropriate time it will be a matter for us to discuss with the SPA whether they meet the war-crimes threshold, but there are certainly serious allegations currently being investigated."
Warwick said the case of Baha Mousa, an Iraqi hotel receptionist who died after being interrogated and abused by British soldiers more than a decade ago, remains "a live criminal investigation".
He added: "There are lots of significant cases that we are investigating and at the appropriate time it will be a matter for us to discuss with the SPA (Service Prosecuting Authority) whether they meet the war-crimes threshold, but there are certainly serious allegations currently being investigated."
Human rights charities have called for the investigations to be sped up, in the hopes of reaching some conclusions before the deadline in 2019.
Carla Ferstman, director of the human rights charity Redress, told the Independent: "The incredibly slow pace at which Ihat is investigating allegations of criminality committed by UK soldiers against Iraqi civilians is wholly unacceptable.
"Things seem to still be moving at a snail's pace. We call upon the Government to ensure Ihat can, and does, do what it was set up to do, and to do it now. This cannot be a whitewash."
A Ministry of Defence spokesperson said: "The vast majority of UK service personnel deployed on military operations conduct themselves professionally and in accordance with the law.
"The MoD takes all allegations of abuse or unlawful killing extremely seriously. Where there is sufficient evidence, members of HM Forces can be prosecuted. It is estimated that the Ihat's work will take until the end of 2019."