A Government investigation into allegations of abuse by British armed forces in Iraq is unfit for purpose and should be scrapped immediately, a parliamentary inquiry is expected to conclude.
MPs will also say the Ministry of Defence (MoD) is responsible for creating a system that allowed Phil Shiner, the disgraced human rights lawyer, to bring criminal cases against former soldiers on an "industrial scale", the Sunday Telegraph said.
The Iraq Historic Allegations Team (Ihat), which was established in 2010 to probe claims of abuse of civilians following the 2003 invasion, is reported to have cost £60 million to date.
Johnny Mercer, the Tory MP presiding over the inquiry, said there is a "rotten core" of civil servants in the MoD who acted autonomously from ministers or military figures.
The MoD said it was obliged to investigate criminal allegations and the existence of Ihat kept British soldiers from being hauled through international courts.
The Defence Sub-Committee's report on the support given to former and serving personnel who face legal proceedings is due to be published on February 15.
Since its launch there have been 3,392 cases lodged with Ihat, two thirds of which were brought by Shiner and his firm, Public Interest Lawyers (PIL).
The allegations against British military personnel have ranged from low-level mistreatment of civilians to claims of torture and murder.
Mr Shiner was struck off on Tuesday after a string of misconduct charges against him, including five of dishonesty, were found proven following a Solicitors Disciplinary Tribunal hearing.
There have been calls for the lawyer to face criminal prosecution and the National Crime Agency is said to be reviewing evidence from the Legal Aid Authority.
Among its findings, the parliamentary report is expected to question why PIL was paid by Ihat to help it with its inquiries.
It is also likely to criticise the MoD for paying the firm more than £200,000 after Mr Shiner had been reported to the Solicitors Regulation Authority, according to the Sunday Telegraph.
Mr Mercer, a former Army captain, told the newspaper: "I have made my distaste for the methods and behaviour of Ihat - and the MoD's complicity in it - very obvious over the last year.
"The evidence has been clear and I look forward to publishing our report a week Wednesday.
"I am pretty clear where the problems lie.
"There is a rotten core of civil servants in the MoD who have made decisions without ministers or military input, and have in the process demonstrated a disturbing lack of understanding or respect for the more subtle qualities that bind an army together and make men fight for each other or a cause.
"Things have improved this year but, prior to my investigation, there was no heed whatsoever paid to how this process has affected our people. That is a deep regret of mine."
The report is expected to call for Ihat, which is made up of mostly civilian investigators, to be replaced by a team from the military police.
An MoD spokeswoman said: "The Government is legally obliged to investigate criminal allegations and the courts are clear that if Ihat did not exist, British troops could be dragged through international courts.
"We're committed to reducing Ihat's caseload to a small number of credible cases as quickly as possible.
"We are determined to stop spurious legal claims against our troops and tackle the likes of Phil Shiner, who have abused our legal system.
"The Defence Secretary insisted that the MoD submit evidence on Shiner's actions due to the distress he caused to soldiers. That led to Shiner being struck off. Now we are taking steps to ensure this abuse cannot happen in the future."