Andrew Malkinson, who served 17 years in jail for a rape he did not commit, had his conviction overturned by the Court of Appeal in July.

The complaints relate to an allegation regarding the failure to retain items of evidence and the failure to reveal information relating to two witnesses who gave evidence to the trial, the Independent Office for Police Conduct (IOPC) said.

It said its casework team "highlighted significant issues" with Greater Manchester Police's investigation into the complaints and "identified several outstanding lines of inquiry".

IOPC director of operations Amanda Rowe said: "Given our concerns over Greater Manchester Police's handling of the complaints - and the significant public interest in a case that led to a man spending 17 years in jail for a crime he didn't commit - our involvement will ensure there is thorough scrutiny of the actions of police involved.

"Our investigation, which will be carried out independently of the police, will focus on the specific allegations raised in Mr Malkinson's complaints.

"We are not reviewing the original criminal investigation, nor do we have the power to do so.

"We are in contact with the government about its broader inquiry into the wrongful conviction. We will continue to work with the chair and inquiry team so that our work and theirs is aligned to ensure that the actions of GMP are fully examined."

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An inquiry was ordered into the handling of Mr Malkinson's case last month.

While it is independent, it is not statutory and therefore is not able to compel people to come before it.

Greater Manchester Police, the Crown Prosecution Service and the Criminal Cases Review Commission (CCRC) will all have their roles in Mr Malkinson's conviction and imprisonment reviewed.

At the time Mr Malkinson said: "I spent over 17 years wrongly imprisoned and so I hope that my lawyers and I will be given the opportunity to feed into the inquiry's terms of reference.

"I had to take the police to court twice to force them to hand over evidence.

"The CCRC has so far refused to apologise and take accountability. So, naturally, I am concerned that witnesses from these agencies may not cooperate and hand over all the evidence."

He added: "If there is any obstruction by the agencies involved, then the inquiry needs to be made statutory so that they can be compelled to hand over evidence.

"I want to see serious, profound changes in our justice system coming out of this. My case shows that the police cannot be trusted to investigate impartially or act as faithful gatekeepers to the evidence."