By Martin HickmanAndy Coulson personally authorised cash payments to the News of the World's private detective which led to the phones of three royal aides being hacked, a court heard today.Giving evidence for the third day at the phone hacking trial, the paper's former royal editor Clive Goodman said that in 2005 he had gone to Mr Coulson, the editor, to seek approval for £500 weekly payments to Glenn Mulcaire.He also said that he showed Mr Coulson a transcript of a hacked voicemail left by Prince Harry to prove the truth of a story about him asking his private secretary for help with his military training.Emails between Mr Goodman and Mr Coulson discussing the work of "matey" - which Mr Goodman said were references to Mulcaire - were also read to the court.Explaining phone hacking at the NoW, Mr Goodman - who denies paying police to obtain three royal phone directories - said senior journalists at the Sunday tabloid had been doing hacking on an "industrial-scale".However, he added that he had only begun to do it himself in 2005 after being criticised by Mr Coulson (whom he has described as a bully) for "under-performing."On 16 August 2005, shown to the court, Mr Coulson had emailed Mr Goodman: "I need a story this week, Clive. Something of substance." On 20 August 2005, he had complained Mr Goodman's Blackadder column was "way, way off the pace this week."Billy Bragg, Rod Liddle - not exactly the new brief is it?", Mr Coulson wrote.Mr Goodman told the Old Bailey that after the News of the World had threatened to reduce Mulcaire's £2,000 weekly payments, the private detective had approached him with an idea.Mr Goodman said: "He explained he was pretty sore because he felt the News of the World was trying to cut his budget by £500 a week... he was trying to make up the shortfall."He offered me a project - that he would provide DDNs [direct dial numbers for voicemail inboxes] and PINs for three people connected to William and Harry, if you provide names."Mulcaire, he said, had suggested he had connections with the security services and some of this information would come from "piggy-backing" the spies, who were "monitoring" the princes.Mr Goodman said that because another senior journalists was closely guarding Mulcaire's hacking, Mulcaire's £500 weekly top-ups would have to be approved by Mr Coulson.In October 2005, he said, Mr Coulson agreed to a two-month trial of the "Alexander" project - Goodman's codename for Mulcaire.At a meeting on 28 October 2005, he said he and Mr Coulson had "discussed the project, how it was going... and whether it would actually produce a story."On 25 November 2005, the court was told Mr Goodman emailed Mr Coulson: "Andy, got a second on extending the matey trial, please?"Mr Goodman's counsel, David Spens QC asked Mr Goodman: "Matey was who?," to which he replied: "That was Glenn Mulcaire."Mr Coulson emailed his response: "Another month."A message left by Prince Harry for his aide Jamie Lowther-Pinkerton asking for help with an essay for this training at Sandhurst was hacked by Mr Goodman.The former royal editor told the court: "I had to show the transcript both to the editor, Andy Coulson, and to [another executive] so they could assess for themselves how strong a story it was."On 9 December 2005, Mr Goodman emailed Mr Coulson about the story, telling him: "As you know, it is 100% fact."Mr Spens asked: "Why are you?" [sure Mr Coulson knew it was 100% fact?], to which Mr Goodman replied: "Because he had a transcript of the message."The News of the World concealed the source of the story by printing false facts about the prince's request to his aide.Later, Mr Goodman updated Mr Coulson on the Alexander project, emailing him on 3 February 2006 that in exchange for £4,000 cash Mulcaire had provided £3,850 worth of stories. Aware that the paper was again trying to trim payments to Mulcaire, Mr Goodman added: "This contact has been increasingly productive, especially since Prince William started at Sandhurst."Mr Goodman went on: "A few weeks ago you urged me to find new ways of getting into the family, especially William and Harry and I came up with this."It's safe, productive and cost-effective and I am convinced it will become a story goldmine for us if we let it continue a few weeks longer."However Mr Coulson emailed Mr Goodman later that day, saying: "I'm sorry, it has to go."Mr Goodman responded: "Ok, you're the boss - but it will be a pretty devastating loss to my network."The court heard that Mulcaire continued supplying the paper with royal stories and tip-offs on an ad hoc basis.In April 2006, for instance, there was a hacked message about Prince Harry and an unidentified woman. On 28 April 2006, Mr Coulson emailed Mr Goodman: "How do we know Harry true?"Mr Goodman replied: "It was from the same source we had on a retainer. We know it is true, but I have to blag a confession out of Paddy [royal press secretary Paddy Harverson] tomorrow."He told the court: "By mentioning the source he [Mr Coulson] would know it was a voicemail and he would know it was true.Mr Goodman said that the only reason the emails still existed was because of action he took after he was arrested in August 2006.He told the court: "Following my arrest for phone hacking I was very concerned I was going to be left high and dry for all hacking activity at the News of the World, so I went to an Internet cafe using a Hotmail address and I downloaded as many emails as I could at the time about hacking - because I was frightened I was going to be left high and dry."Mr Goodman added that the other source of emails was the internal inquiry into his subsequent claim of unfair dismissal.He told the Old Bailey: "The only emails that exist from that era are the ones that I obtained after my arrest."Mr Goodman, who will continue giving evidence tomorrow, denies conspiring to commit misconduct in public office.Mr Coulson, who will probably start giving evidence next week, denies conspiring to hack phones and conspiring to commit misconduct in public office.