By Ian Dunt Follow @IanDunt
Rupert Murdoch's media empire must be broken up in the wake of the phone-hacking scandal, Ed Miliband has said.
The comments were echoed by the deputy prime minister, who suggested that plurality tests be applied on a day-by-day basis, rather than just when a specific business transaction takes place.
Mr Miliband has generally been credited with being ahead of the curve in responding to the phone-hacking scandal and Nick Clegg's offering of similar measures suggests that the government is trying to keep up as attitudes harden towards the media mogul.
"I think that we've got to look at the situation whereby one person can own more than 20% of the newspaper market, the Sky platform and Sky News," Mr Miliband told the Observer.
"I think it's unhealthy because that amount of power in one person's hands has clearly led to abuses of power within his organisation. If you want to minimise the abuses of power then that kind of concentration of power is frankly quite dangerous."
Mr Clegg told the Andrew Marr programme: "At the moment you can only apply this test of plurality when you've got a business transaction you've got to examine.
"I don't see why we can't apply it all the time. Whether its fitness and properness test, whether it's the plurality test, it's being applied in a very snapshot way."
Commentators have credited Mr Miliband with correctly assessing the scale of the phone-hacking scandal in its early stages and adopting a leading role since it began.
That assessment contrasts badly with the prime minister, who has struggled to seem on top of affairs as they rumble forward.
The comments come as Liberal Democrats manoeuvre to take even his remaining parts of BSkyB from Mr Murdoch's grasp.
Simon Hughes, Lib Dem deputy leader, and Tim Farron, media spokesman, wrote to Ofcom to ask that it applies its 'fit and proper' test on News Corp's current 39% share of the satellite broadcaster.
Any negative finding from the regulator would be devastating for Mr Murdoch, who is still picking up the pieces after being forced to give up his long-held dream of fully controlling BSkyB.