Former Daily Mirror editor Piers Morgan has been questioned by Scotland Yard detectives in connection with claims of phone-hacking.
The journalist was previously interviewed under caution at the end of 2013 by officers investigating claims of illegal interception of voicemails by Mirror national newspaper journalists.
A Metropolitan Police spokesman said: "A 50-year-old man was interviewed under caution on April 21 2015 by officers from Operation Golding in connection with suspected conspiracy to intercept telephone voicemails.
"He was interviewed by appointment. He was not arrested."
The former tabloid boss tweeted: "At 1.30pm today, I left a second police interview re Mirror hacking investigation. At 4.30pm, The Guardian phoned me about it."
In a statement, he said: "Some time ago I was asked to attend an interview with officers from Operation Golding when I was next in the UK.
"This was further to a previous voluntary interview I provided in December 2013.
"I attended that interview today.
"As this is an ongoing investigation, I am unable to comment further until its conclusion."
To date, two former Mirror journalists – Dan Evans and Graham Johnson – have pleaded guilty to phone-hacking while at the newspaper group.
A further four journalists are known to be on bail after being arrested for hacking offences. They are former Sunday Mirror editor Tina Weaver, former Sunday People editors James Scott and Mark Thomas and Sunday People deputy editor Nick Buckley.
Last month, a two-week High Court hearing was held to determine compensation payouts for eight Mirror phone-hacking targets. The claimants' barrister David Sherborne described hacking as "rife" across the three Mirror national titles. Matthew Nicklin QC, for Trinity Mirror, denied this claim.
At the end of last month, The Times reported that the Met Police was “sitting on dozens of unopened bin-bags of material” gathered by officers investigating Trinity Mirror national newspapers.
According to The Times, the “sacks” have been gathered by officers from Operation Golding – which is investigating phone-hacking across the Mirror titles. Operation Elveden officers are also investigating allegations of payments to public officials at the newspaper group.
Since 2011, at least 64 journalists have been arrested under Met Police investigations into phone-hacking, payments to public officials and computer-hacking.
According to a Press Gazette Freedom of Information request, the Met had spent £33.5m on these investigations – excluding legal fees – to 30 September 2014.
At the time of the FoI, which was responded to on 17 December, 99 journalists had been suspected of wrongdoing.
Morgan was editor of the Daily Mirror from 1995 until 2004, when he was sacked after the newspaper ran pictures claiming to show British soldiers abusing Iraqi prisoners which were later discovered to be fakes.
He is now editor-at-large for the Mail Online in the US.
He has always denied any involvement in phone-hacking.