Police assured the barrister prosecuting a News of the World reporter for phone-hacking that there was no evidence against any of the paper's other journalists, the Leveson Inquiry heard today.
David Perry QC said that at the time he saw no material that would have enabled a criminal case to be brought against Andy Coulson, then editor of the Sunday tabloid, or any other News International employees.
Former News of the World royal editor Clive Goodman and private investigator Glenn Mulcaire were jailed in January 2007 after they admitted intercepting voicemail messages left on royal aides' phones.
Mr Perry, who prosecuted the case for the Crown, told the press standards inquiry that he raised the question of whether other journalists were also involved in phone-hacking at a case conference with Scotland Yard detectives on August 21 2006.
"My recollection of this is that I asked whether there was any evidence implicating any other individual employed by News International in the criminality that we were looking at in this particular case," he said via videolink from Northern Ireland.
"I was concerned to discover whether this went further than just the particular individuals with which we were concerned, and I think I was conscious in my own mind that the question had to be whether it was journalists to the extent of the editor."
He added: "We were informed there was no such evidence. I cannot recall which officer gave that reply."
The Metropolitan Police Service was widely criticised for failing to reopen its phone-hacking investigation after the Guardian published an article on July 9 2009 alleging there were more journalists and many more victims involved.
Mr Perry was asked to prepare a short note for the Crown Prosecution Service on July 14 2009 setting out the advice he was given by detectives in 2006.
He wrote: "We did inquire of the police at a conference whether there was any evidence that the editor of the News of the World was involved in the Goodman-Mulcaire offences.
"We were told that there was not (and we never saw any such evidence).
"We also inquired whether there was any evidence connecting Mulcaire to other News of the World journalists.
"Again we were told that there was not (and we never saw any such evidence)."
Robert Jay QC, counsel to the inquiry, asked whether police and lawyers had speculative discussions at the August 2006 case conference about any possible circumstantial evidence against other journalists.
Mr Perry replied: "It is certainly possible, although I have no recollection of it.
"I think from my point of view I would have been looking to see whether there was a possibility of a case rather than whether there was something that was speculative. We can all speculate...
"I certainly don't think I saw anything that would have enabled me to present a case on the basis of any inference or circumstantial evidence."
Mr Perry could not recall whether in 2006 he was shown the "For Neville" email, which contained transcripts of illegally intercepted voicemail messages and was apparently destined for the News of the World's chief reporter Neville Thurlbeck.
But he later advised that the email had no real evidential value against Mr Thurlbeck, the inquiry heard.
Former director of public prosecutions Lord Macdonald said in a written statement for the inquiry: "I would have expected that if the Metropolitan Police Service had indicated that police were in possession of evidence to implicate other individuals within News International, the CPS (Crown Prosecution Service) would have advised them to continue with their investigation.
"As there was confirmation to the contrary, the CPS was unable to provide this advice."
Lord Macdonald also spoke of his fears that the Leveson Inquiry could lead to a clampdown on whistle-blowers who contact the media with concerns about wrongdoing within their organisations.
"My fear is that if the internal remedy is the only route for whistle-blowers, too often that would result in suppression in one form or another," he said.
"We can all think of cases in which it could be critically in the public interest for a whistle-blower to go straight to the newspaper or a media organisation, and I think it's strongly in the public interest from time to time that occurs."
The eminent barrister added: "It's my personal view, if you forgive me for expressing it, it would be a matter of significant regret if this inquiry resulted in further impediments to that process."
The inquiry heard that prosecutors knew there was evidence that many celebrities were phone-hacking victims more than two months before Goodman and Mulcaire were arrested on August 8 2006.
Senior CPS lawyer Carmen Dowd wrote in a briefing note dated May 30 2006: "A vast number of UVMs (unique voice mails) belonging to high-profile individuals (politicians and celebrities) have been identified as being accessed without authority - these may be the subject of a wider investigation in due course."
The inquiry has heard that detectives seized 11,000 pages of names and telephone numbers from Mulcaire when he was arrested, and had identified 200 potential phone-hacking victims by the time of the August 21 2006 case conference.
The inquiry, sitting at the Royal Courts of Justice in London, was adjourned until April 23, when it will begin hearing from newspaper proprietors.