Detectives investigating historical sex crimes should not be ordered to believe alleged victims "unconditionally", Britain's top police officer has said.
Sir Bernard Hogan-Howe said officers should investigate allegations with an "open mind" rather than follow the current policy of presuming claims to be true.
Suspects should also be offered anonymity before they are charged because "reputations may be tarnished" even before officers decide whether an allegation has merit, he added.
His comments came after he announced a judge-led review of Scotland Yard's controversial handling of claims of a VIP paedophile ring in Westminster amid mounting pressure over Operation Midland.
Writing in the Guardian, the Metropolitan Police commissioner said "public confidence has been affected" by the Met's handling of investigations into Lord Bramall and other high-profile figures.
The way officers investigate historical sex claims involving public figures would be part of the review, Sir Bernard added, suggesting a shake-up of policy to make it "more neutral".
He said a review of the Met's approach to rape cases showed the force's policy moved from, in 2002, accepting an allegation as "truthful" in the first instance to being in line with guidance from the HM Inspectorate of Constabulary in 2014 which stipulated the victim should always be believed.
Sir Bernard said: "The public should be clear that officers do not believe unconditionally what anyone tells them. They are listened to, sometimes at length, before the decision is made to begin an investigation.
"A good investigator would test the accuracy of the allegations and the evidence with an open mind, supporting the complainant through the process. This is a more neutral way to begin than saying we should believe victims, and better describes our impartial mindset.
"Emotionally, though, it may not be enough to give victims confidence in our approach."
But he admitted the change in approach created a tension that was "hard to reconcile".
The embattled Scotland Yard boss again refused on Wednesday to bow to calls to apologise to Lord Bramall, 93, amid fierce criticism over the conduct of Operation Midland, which saw police raid the home of the former D-Day veteran.
The case against Lord Bramall was later dropped.
The findings of the review, to be led by former High Court judge Sir Richard Henriques, will be published later in the year, although the full report will remain confidential.
But it has been dismissed as a "PR campaign" by former Conservative MP Harvey Proctor, who was questioned under the controversial inquiry before facing no further action.
Operation Midland, which had cost £1.8 million as of November last year, centred on allegations by a man known as "Nick", which were described by a detective at the time as "credible and true".