Journalists in The Sun newsroom were said to be outraged today following the arrest at 6.30am this morning of reporter Rhodri Phillips.
Phillips was arrested at his home by detectives working on the Tuleta probe into allegations of computer hacking. The Met has since revealed he has been arrested on suspicion of "handling stolen goods".
Phillips is at least the 19th journalist from The Sun newsroom to be arrested in recent months.
Some 18 journalists have been arrested and released on bail by police working on the Elveden Inquiry into allegations of bribery and corruption including many of the paper's most senior and respected names.
Insiders at The Sun believe the Phillips arrest stems from an incident some years ago when the paper was contacted by a tipster who claimed to have found an MP's phone.
Phillips was apparently tasked with investigating the story.
Press Gazette understands that once the unlocked phone was looked at it was found that the MP in question was not high profile enough to be worth writing a story on so the matter was left.
Insiders believe the latest arrest stems from the trawl through emails and other records by News Corp's Management and Standards Committee.
News Corp chairman Rupert Murdoch stated on 1 May that the MSC had completed its internal review of The Sun, Times and Sunday Times. But either its searches are ongoing or the Met Police is only now acting on information received earlier.
Times crime editor Sean O'Neill tweeted today: 'Sun reporter arrested today had answered a call to nightdesk from someone who said he'd found MP's phone on a train. Went to check info... Examined phone to see if authentic and is there a 'security breach' story. Wrote email memo to newsdesk. No story published.. ..is that an offence that warrants an @metpoliceuk dawn raid on a family w v young kids? Sounds like a reporter doing his job."
One well-placed senior Fleet Street source told Press Gazette: 'Rhodri Phillips is the most decent straight reporter you could ever meet. This is an absolute outrage."
A source described the current mood in the Sun newsroom as "mutinous" in the light of the latest arrest.
Sun columnist Jeremy Clarkson tweeted this afternoon: 'Half the police are at the Olympics and the other half are busy arresting journalists. I may do some burglary."