Newsnight presenter Jeremy Paxman has told the Leveson inquiry into press standards that Piers Morgan told him how to hack phones at a dinner in 2002.
Paxman said the former Daily Mirror editor was present at a dinner he attended at Mirror headquarters in Canary Wharf, where Morgan told him if you didn't change your default security code "you were in, his words, a fool".
Also at the dinner, he claimed, were Sir Victor Blank, the chairman of Trinity Mirror, as well as Phillip Green and Ulrika Jonsson.
"Have you got a mobile phone?" Morgan asked according to Paxman. "I said yes," said Paxman.
"Have you got a security setting," Morgan asked, according to Paxman.
"I didn't know what he was talking about" said Paxman.
He then explained that the way to get into someone's messages was to "go to the factory default setting and press either 0000 or 1234 and that if you didn't put on your own code, his words, 'You're a fool'."
"It was clearly something he was familiar with."
Morgan has always denied any wrongdoing in relation to accusations of phone hacking in the wider media.
On Twitter Morgan joked that was the "last time I'm inviting Jeremy Paxman to lunch":
Paxman also alleged that at the dinner Morgan teased Jonsson about a conversation he claimed to have heard between her and England manager Sven Goran Eriksson.
Paxman said Morgan affected a mock Swedish accent and that the atmosphere was "close to bullying".
The presenter said he remembered the lunch for two reasons: he wondered why he had been invited and because of what Morgan said.
"Mr Morgan was teasing Ulrika that he knew what had happened in a conversation between her and Sven-Goran Eriksson," said Paxman. "It was a rather bad parody."
"I don't know if he was repeating a conversation he had heard or he was imagining this conversation. To be fair to him I should imagine both possibly because he probably was imagining it."
At the end of his evidence Paxman said to Lord Justice Leveson: "Your challenge is to stop yourself becoming a total irrelevance."
Leveson replied that his intention was not to produce a document just to sit on the second shelf of journalism professors.
"As high as the second shelf, eh?" Paxman replied.
The Leveson Inquiry was set up by Prime Minister David Cameron last July in response to revelations that the News of the World hacked murdered schoolgirl Milly Dowler's phone after she disappeared in 2002.
The hearing is currently focusing on relationships between politicians and the media.
Earlier Andrew Marr, former BBC political editor and ex-editor of the Independent newspaper shared his insights.
He said after Tony Blair came to power in 1997, New Labour favoured some journalists because they worked for Rupert Murdoch.
He said: "I think a decision was taken that it was very important to keep the Murdoch press as far as it was possible - it wasn't always possible - onside, to have a close relationship with their leading journalists and reporters."