The Royal Military Police are to be removed from their role in probing allegations of torture and ill treatment by more than 100 Iraqis, it was announced today.
That role will now be carried out by the Royal Navy Police, said Armed Forces minister Nick Harvey.
The move follows a critical ruling by the Court of Appeal.
Some 128 Iraqis complain that the UK Armed Forces were guilty of systemic abuse of detainees between March 2003 and December 2008 when they controlled the Basra area in southern Iraq.
Three appeal judges said the Iraq Historic Allegations Team (IHAT) set up to investigate the allegations lacked "the requisite independence".
They found that involvement of Royal Military Police investigators could give rise to "the public perception of the possibility of bias".
The court, headed by Lord Justice Maurice Kay, vice president of the Court of Appeal's civil division, declared that the Government had failed to comply with its obligations under Article 3 of the European Convention on Human Rights, which protects against inhuman and degrading treatment.
Today Mr Harvey announced the Government was making changes "to meet the Court of Appeal's concerns".
Mr Harvey said he had "absolute confidence" in the ability and integrity of the Provost Marshal (Army) and the RMP to conduct appropriate and effective investigations.
He said the court had emphasised no evidence of any member of the Army's Provost Branch actually being involved in misconduct against detainees.
But he accepted the court's conclusion on the "public perception" of the possibility of bias.
"I have therefore decided to remove the Royal Military Police role in relation to the IHAT.
"Instead, that role will be carried out by the Royal Navy Police, which is headed by the Provost Marshal (Navy)."
Mr Harvey said the change was already being implemented and would be completed by April 1.