The hacking of Kate Middleton, Prince Harry and Prince William's voicemails for the News of the World were dismissed in court as mere "flourishes".
Private detective Glenn Mulcaire was just "showing off" when he hacked the young royals and future Duchess of Cambridge in late 2005 and 2006, former NotW royal editor Clive Goodman said.
Under cross examination, he denied lying to the Old Bailey trial about his involvement in their hacking or that he specifically told the then editor Andy Coulson about it.
Coulson is accused of approving Goodman's Alexander Project to pay Mulcaire to hack three royal aides from autumn 2005 to spring 2006.
Prosecutor Andrew Edis QC showed the court phone records highlighting Ms Middleton's phone was hacked from December 21 2005 and Prince William was first hacked on January 29 2006.
Goodman, 56, said he was "astonished and surprised" when he first found out Mulcaire had managed to get into Ms Middleton's voicemails.
Mr Edis asserted: "You would never have gone anywhere near targets of that degree of sensitivity without the authorisation of the editor."
But Goodman replied: "I do not remember having a direct conversation with him about these specific targets."
The lawyer said: "Are you seriously saying you never mentioned this aspect to Mr Coulson?"
Goodman replied: "What we discussed was the Alexander Project which was Helen Asprey, Jamie Lowther-Pinkerton and Paddy Harverson.
"These other royal voicemails, I think Glenn Mulcaire thought of them as flourishes to show what he could do."
Mr Edis went on: "The reason you never said Coulson knew all about Prince Harry, Prince William and Kate Middleton was because in order to do that you would have to accept you had done it."
Goodman said the Crown Prosecution Service at the time had "ringfenced" the hacking case so as not to "embarrass the royal family".
But he added: "These members of the royal family have now been embarrassed in this trial."
Mr Edis said: "It cannot be true you forgot Prince William. It was a lie."
The witness denied he had lied earlier in his evidence on the subject, saying he had been confused before the CPS had clarified he would face no further charges in relation to phone hacking.
Goodman, of Addlestone, Surrey, is accused of conspiring with Coulson, 46, of Charing, Kent to commit misconduct in public office.
Coulson is also accused of conspiring to hack phones with former NotW editor Rebekah Brooks and retired NotW managing editor Stuart Kuttner. All seven defendants deny the charges against them.
The court has heard that Goodman and Mulcaire were caught hacking in August 2006 and were jailed after pleading guilty.
The direct hacking of members of the royal family and Ms Middleton emerged in evidence in the fresh trial.
Later, as Goodman completed his evidence, the judge Mr Justice Saunders addressed the jury on the trial's progress.
He said the case had been delayed because of considerations for Goodman's health.
He told jurors: "Our aim is that you will retire to consider your verdicts on Monday June 9."