A Sun newspaper reporter has been found guilty of receiving story tips from a Heathrow Airport anti-terror officer.
Anthony France, 41, from Watford, had denied aiding and abetting PC Timothy Edwards to commit misconduct in a public office between 2008 and 2011.
Edwards sold 43 stories to France, 38 of which made the paper, in exchange for more than £22,000.
France had said he was a "man of good character not involved in crime". He will be sentenced on 29 May.
His mother burst into tears as he left the dock after being found guilty.
The Old Bailey heard that Edwards, 49, sold the information while working at Heathrow Airport in SO15 Counter Terrorism Command.
But the jury was not told that Edwards had pleaded guilty to misconduct in a public office and was jailed for two years in 2014.
The trial was part of the Met Police's Operation Elveden, which is investigating alleged payments to police and officials in exchange for information.
The court heard that Edwards had passed on details which included airline pilots being breathalysed.
France was also told of a model erupting into a rage after "catching her boyfriend romping with a woman next to him".
But France told the jury he had never been advised by anyone at the Sun that speaking to a police officer - or any public official - could be breaking the law.
He also said he would never have become involved in receiving story tips from Edwards if he had known it was illegal.
When asked what he would have done if he thought talking to Edwards might be illegal, he said: "I would never have got involved with it. I would have told him to get lost."
The court was told that Edwards had been "given" to France as a source.
He was told by a colleague "I've spoken to a lawyer and it's fine" after meeting Edwards at a pub in 2008.
Det Ch Supt Gordon Briggs, who leads Operation Elveden, said France and Edwards had been in a "long-term, corrupt relationship".
He added: "Edwards was not a whistleblower, he obtained confidential information in the course of his duties and leaked it for financial gain.
"Corrupt relationships of this kind undermine confidence in the police service and harm the public interest. Officers found guilty of acting in this way merit criminal sanction.
"Journalists who encourage or aid and abet their corrupt actions, and do so without reasonable excuse or justification, are equally culpable."
The BBC's Gaetan Portal says that France's conviction is significant, because he is the first journalist to face trial under Operation Elveden since the CPS changed its guidance to prosecutors last month.
That guidance effectively raised the bar for prosecution of journalists, for payments to public officials, so that only payments to police officers over a period of time would see the journalist end up in court.
Those journalists who had paid civil servants, health workers or prison staff had the charges against them dropped.