An agreement between the BBC and police which led to a raid on Sir Cliff Richard's home being broadcast live around the world "certainly interfered with his privacy and may well have caused unnecessary distress", according to an independent report.
A former chief constable has said South Yorkshire Police (SYP) should never have a made a deal with the broadcaster – a decision taken after BBC reporter Dan Johnson went to the force saying he knew they were investigating the veteran entertainer.
In his report, Andy Trotter said: "The search at Sir Cliff Richard's apartment, and the nature of the allegation, generated considerable publicity across the world, certainly interfered with his privacy and may well have caused unnecessary distress."
He said: "Whatever the motivation and good intentions of those involved from SYP, the outcome has been bad publicity for the force, the Chief Constable being summoned to HASC (Home Affairs Select Committee), criticism from the media and politicians, complaints from the public, abuse on social media and a public spat with the BBC.
"More importantly, people have seen a search on Sir Cliff Richards's apartment unfold on television with details of a serious allegation put into the public domain prior to him being interviewed by the police.
"The force can argue that the search was carried out successfully and there was no interference to the investigation that the threat of prior publication was avoided. That is true but at considerable cost to the reputation of the force which could have been avoided by the individuals concerned."
Trotter's report was ordered by former South Yorkshire Police and Crime Commissioner (PCC) Shaun Wright after detectives searched the 74-year-old star's Berkshire apartment in August while film crews from the corporation, including one in a helicopter, caught the event on camera.
It was released by the PCC's office following a Freedom of Information request.
Following the raid, Richard was interviewed by detectives investigating a claim of a sex crime involving a young boy, but was not arrested or charged.
The report concluded that South Yorkshire Police should not have confirmed "highly sensitive and confidential" details to the BBC or facilitated a meeting between a senior detective and a corporation reporter.
In October MPs on the Home Affairs Committee branded South Yorkshire Police "inept" over their handling of the event and said the force should have refused to co-operate with the BBC.
The Home Affairs Select Committee also criticised the BBC for its decision not to allow reporter Johnson to appear before them.
A statement from Richard's lawyers at the time said the coverage caused "immeasurable harm" to the star.
A BBC spokesman said: "The Home Affairs Committee has already endorsed the way the BBC handled this story."
The new South Yorkshire PCC, Dr Alan Billings, said: "I have read the report from Mr Andy Trotter commissioned by my predecessor in August 2014.
"Mr Trotter outlines six recommendations in his report. I have had discussions with the Chief Constable and he advises me that all recommendations relating to South Yorkshire Police will be implemented."
The report – which is dated 29 September 2014 – cleared SYP of publicity-seeking.
Trotter concluded: "I am content that those involved at SYP were motivated by trying to ensure the integrity of the investigation and by no other consideration.
"I came across nothing to suggest that the force was seeking publicity or involved in any improper relationships with the media.
"However, through a failure to foresee the consequences of their decisions, they put the force in a position which was difficult to defend and which could, and should, have been avoided."
Trotter said both Carrie Goodwin, the head of communication for the force, and Detective Superintendent Matt Fenwick, the officer leading the inquiry, were adamant that Dan Johnson said his source was Operation Yewtree – the Metropolitan Police inquiry into allegations of child abuse by Jimmy Savile and others.
He said Johnson has denied this but the BBC has acknowledged the original source was not SYP.
Trotter also said there were different accounts from SYP and Johnson about how much the BBC reporter knew before he contacted them.
Johnson said he went to them with just a name and the police filled-in the details. But SYP "believed he had as much knowledge of the case as they did and that he was ready to run the story", the report said.
Trotter said: "The suggestion that a journalist could just mention a name of a well-known person to a police head of communications and a senior investigating officer, and get them to reveal details of a highly sensitive and confidential investigation, is not one I believe to be credible."
In his report, he said: "It is hard to understand why Dan Johnson approached SYP in connection with this case if he only had Sir Cliff Richard's name and no other details.
"Had the leak come from SYP then that would explain why he went to them, but the BBC have confirmed that SYP was not the source of the leak.
"There is always the possibility that SYP were to some extent 'conned' by Dan Johnson into revealing more information than he already had, but both Carrie Goodwin and Matt Fenwick are adamant that Dan Johnson knew as much as they did about the case and that he repeatedly named Yewtree as his source during their discussions before the raid."
He said: "I have not interviewed Dan Johnson but I have no reason to disbelieve Carrie Goodwin or Matt Fenwick, and their accounts of their meeting with Dan Johnson are supported by their notes."
Trotter said: "However, at his brief meeting with Matt Fenwick on the 15 August 2014, and from the BBC's evidence at HASC, Dan Johnson claims never to have mentioned Yewtree and insists he only ever had Sir Cliff Richard's name, and no other details of the investigation."
Trotter said Goodwin and Fenwick both believed that "failure to cooperate with the BBC could lead to the premature release of information from the BBC, and the potential loss of evidence from the search."
He said: "They strongly believed Dan Johnson had a very reliable source and could proceed with his story at any time. Everything that followed was a result of that view."
In his conclusion, the former chief constable said: "By agreeing to cooperate with the BBC the force transferred the risk to themselves and took the blame after the event.
"Had the force refused to cooperate with Dan Johnson I think it was unlikely that he had a story that he could broadcast. If there were real concern that he would go ahead with the story, the force should have considered a complaint to a senior level of the BBC. If the BBC then decided to continue with the story, and thus interfere with the investigation, the force would have done everything it could to have avoided the situation.
"By co-operating the force 'stood the story up' and absolved the BBC of any risk or responsibility for the story. If there had been a leak from Operation Yewtree to Dan Johnson, then by co-operating with him the force allowed him to profit from that relationship. We now know that Dan Johnson is denying that he ever mentioned Operation Yewtree."
Today, in a statement, SYP said: "South Yorkshire Police accepts the findings of the independent review commissioned by the PCC. We will implement all five recommendations in order to improve our dealings with the media."