Scotland Yard made "numerous errors" in its doomed investigation into VIP paedophile allegations, a highly critical report has found.
Retired High Court judge Sir Richard Henriques said the decision to abandon the inquiry should have been taken much earlier.
He identified a catalogue of failings in the £2.5 million Operation Midland, which closed without a single arrest earlier this year.
As key parts of the report were published, Metropolitan Police Commissioner Sir Bernard Hogan-Howe said he "fully recognised" that D-Day veteran Lord Bramall, former Tory MP Harvey Proctor and the late former Home Secretary Lord Brittan were all "innocent of the offences of which they were accused".
He apologised to Lord Bramall, Mr Proctor and Lord Brittan's widow for "the impact of Operation Midland on their lives".
Sir Richard's damning review found 43 failings in Operation Midland, including believing the complainant, a man known as "Nick", for too long; one officer announcing that his claims were "credible and true"; and applying for search warrants with flawed information.
The former judge said: "The principal cause of the many failures in this investigation was poor judgment and a failure to accurately evaluate known facts and to react to them. A major contributing factor was the culture that 'victims' must be believed."
In a letter to Sir Bernard introducing the report, Sir Richard said the principal cause of mistakes in Operation Midland was the decision to search several premises, thereby risking the names of the householders being published.
He wrote: "The decision to search those premises was a grave error of judgment when the several inconsistencies in Nick's interviews are carefully analysed as they should have been prior to the searches."
He concluded that the investigation could have been carried out speedily and without those named by Nick learning of it.
Sir Richard said in the letter that there is an "unjustifiable imbalance" between the scrutiny of complainants and suspects, which was highlighted in Operation Midland.
He said: "The police inspected every piece of paper and recording equipment in the homes of Lord Bramall, Lady Brittan and Mr Proctor, including letters of commiseration and Golden Wedding invitations."
Lord Bramall and Mr Proctor were accused of the gravest of crimes and then left in a state of limbo, Sir Richard said, while Nick was contacted on a regular basis and given "chapter and verse" on the progress of the investigation.
He said much work must be done to improve the police relationship with suspects.
"I have observed the crushing effect that a prolonged investigation can have on innocent suspects and their families," he wrote.
Scotland Yard said that as a result of the review another force, Northumbria, would investigate a claim that "a complainant" had attempted to pervert the course of justice.
Five officers have also been referred to police watchdog the Independent Police Complaints Commission over potential breaches in professional standards linked to Operation Midland.
Deputy chair Rachel Cerfontyne said: "We were advised earlier today that the Metropolitan Police is to refer the conduct of five officers, ranging in rank from sergeant to deputy assistant commissioner, to the IPCC in relation to Operation Midland.
"We understand the conduct of a deputy assistant commissioner will also be referred to the IPCC regarding a different operation.
"We have assembled an assessment team to analyse relevant documentation to be supplied by the force, and provide me with a recommendation. Once I receive that recommendation, I will decide whether there will be an investigation and, if so, what form that investigation will take. I am aware of the significant public interest in these matters and I will announce that decision once I have made it and all concerned parties have been notified.
"We have not received any complaints from individuals who may feel they were adversely affected by the actions of officers involved in Operation Midland but, as in all cases, were such complaints to be referred to the IPCC they would be given due consideration."
Met Deputy Commissioner Steve Rodhouse said: "I do not believe that I, or indeed any officer within Operation Midland, have committed any misconduct. While it is right that lessons should be learned from Operation Midland I want to emphasise that my colleagues and I investigated the allegations made with the best of intentions. Indeed I am grateful that Sir Richard himself recorded that the Operation Midland officers 'conducted this investigation in a conscientious manner and with propriety and honesty'.
"If a further investigation is required then I will, of course, continue fully to co-operate with it."
Sir Richard also reviewed another investigation, Operation Vincente, an inquiry into a separate allegation that Lord Brittan raped a 19-year-old woman.
He found it "involved a grave error of judgment" and it was "obvious" while the peer was still alive that there was not enough evidence to charge him.
"It was also manifest that he was very poorly. I am in no doubt that he should have been informed during his lifetime that no action would be taken," the former judge found.
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