Mark Warwick says investigation into claims of murder and torture is still receiving cases that could put British soldiers on trial

Iraq war veterans may face prosecution for crimes including murder after an investigation into allegations of torture and unlawful killing, the head of the unit investigating the claims has said.

Mark Warwick said there were significant cases and that discussions would be held further down the line over whether they met the war crimes threshold.

UK forces withdrew from Iraq in 2009, although lawyers are continuing to refer cases to the Iraq Historic Allegations Team (Ihat), the government-established criminal investigation into murder, abuse and torture claims linked to the six-year military mission.

Warwick, the former police detective in charge of Ihat, told the Independent: “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 [SPA, which deals with military cases] to prosecute and charge.

“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 [finalising investigations by] 2019 seems realistic,” he added.

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The inquiry’s workload reached 1,515 possible victims by September, of whom 280 are alleged to have been unlawfully killed. 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”.

“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,” he said. “There are certainly serious allegations currently being investigated.”

Warwick said not all allegations would 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?

“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.”

Campaigners have pushed for the pace of the investigation to be speeded up. Ihat’s budget is set at £57.2m, which runs until the end of 2019 – 16 years after the 2003 invasion began.

Carla Ferstman, the 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.”