Trial judge Mr Justice Saunders expressed his “concern” about the comments the Prime Minister made on Tuesday after Coulson was found guilty of plotting to hack phones at the News of the World while verdicts were pending on other charges.
Jurors have now been discharged, not because of his comments but because they failed to reach verdicts on the final charges after nine days deliberation.
On Tuesday Mr Cameron led the way in what the senior judge described as “open season” of political reaction which saw the Chancellor George Osborne, Labour leader Ed Miliband and others follow suit.
Coulson, 46, faces up to two years in prison when he is sentenced next week. However, he will have to wait to see if he will face a re-trial, along with former NotW royal editor Clive Goodman on charges relating to paying a police officer for royal phone directories.
The judge asked the Prime Minister to explain his comments and said he was told by his principal private secretary that he was responding to the guilty verdict “delivered in open court.”
But Mr Justice Saunders said the Prime Minister had “missed the point” and revealed information the jury had not been told for legal reasons.
He said: “My sole concern is to ensure that justice is done. Politicians have other imperatives and I understand that. Whether the political imperative was such that statements could not await all the verdicts, I leave to others to judge.
“The press in court have been extremely responsible in their reporting of this case but when politicians regard it as open season, one cannot expect the press to remain silent.”
Before the jury was discharged, Coulson’s legal team had argued it should be excused from making a decision on the remaining charges as a fair trial could not longer be guaranteed amid such a “maelstrom of reporting”.
Coulson’s lawyer Timothy Langdale QC called the Prime Minister’s comments “ill-advised and premature”, made “to avoid political damage”.
Following the partial verdict, Mr Cameron offered an “unreserved” apology for employing Coulson. He was also criticised by former Lord Chancellor Kenneth Clarke, who described Mr Cameron’s comments as “unwise”. Labour said Mr Miliband had been careful in his own statement not to raise issues of Coulson’s character or the facts of the trial – other than to refer to him as a “criminal”, a fact established by the jury.
Meanwhile, a former union leader whose phone was hacked has called for public scrutiny of the links between those convicted and leading politicians. Andy Gilchrist, ex-general secretary of the Fire Brigades Union, also pressed for prosecutors to establish whether the Proceeds of Crime Act can be used to recover profits made as a result of the conspiracy.
Last night, it was claimed that self-confessed phone hacker Glenn Mulcaire accessed the new identities of individuals under witness protection but Scotland Yard took no action. BBC Panorama reported the Metropolitan Police had evidence in 2006, during a previous investigation into phone hacking, that Mulcaire had accessed the secret information.
Special report: Page 7