The matter was referred to the IPCC by Surrey Police in August last year after the force received information from three newspaper journalists that they were going to publish the allegations.
Mike Franklin, IPCC Commissioner, said today: “It appears from this investigation that unsubstantiated information, perhaps not surprisingly, quickly gained currency in a climate where the relationships between the police and the media are under intense public scrutiny.
“A police officer was criminally interviewed and remained under suspicion for some months, as our investigators sought to establish the facts. We have provided Surrey Police with our report and indicated we see no need for further action.”
Mr Franklin said the terms of the IPCC investigation were specific to the allegations and the police officer concerned.
“The allegations that a Surrey Police officer provided information to journalists during Operation Ruby, and may have been paid for doing so, can only have added to the terrible loss endured by Milly Dowler’s family,” he said.
“Surrey Police, quite rightly, came under a great deal of scrutiny over this issue - the allegations are serious and required independent examination.
“I hope our finding that there was no substantive or factual evidence to support the allegations will provide some reassurance to the Dowler family on this issue at least.”
The IPCC said the Dowler family had seen its report into the specific officer. They are conscious of the fact that other investigations not involving the IPCC are ongoing and have no further comment to make.
The IPCC investigation, which began in August last year, centred around claims that a Surrey Police officer gave information about the Milly murder probe to the News of the World.
It had received a voluntary referral from the force about an allegation that an officer gave information to the newspaper in relation to the investigation in 2002, and a decision was made to investigate independently.
A month before the investigation began, Surrey Police confirmed the unnamed officer was “given words of advice” and permanently taken off the probe in 2002 for telling a friend, a retired police officer, details about the investigation.
At the time, a spokeswoman said there was no suggestion that any officer had shared information with The News of the World.
She said a serving colleague reported the officer after they were told about the “inappropriate disclosure” by the person who had heard it.
Surrey Police said they welcomed the findings of the IPCC investigation.
In a statement, the force said that, at the time the allegations emerged last year, it was not aware of the source and took the decision to refer the matter to the IPCC in order to be “open and transparent”.
Immediate disciplinary action was taken in 2002 against the officer concerned after it became apparent he had provided confidential details about the investigation to a retired police officer friend.
He was immediately and permanently removed from the inquiry and from the Major Crime Investigation Team.
The force said it has since emerged that the allegation originated from a “disgruntled former officer”.
“It is now apparent that this recent allegation originated from a disgruntled former officer who resigned from Surrey Police pending a misconduct hearing following a criminal conviction at Aldershot Magistrates’ Court in 2010,” the force said.
“He provided an account of the 2002 events in a phone call to an MP’s office in which he made a number of false allegations including that the officer in question had met a News of the World reporter at a social function and passed on confidential information around the Milly Dowler case.
“The MP then passed that claim on to journalists.
“The former officer did not provide the IPCC investigation with any specific details or evidence to support his allegations and the Commissioner’s report has described the information as ‘supposition and rumour’ at best.”