Vince Cable, the British business secretary, has ordered media regulator Ofcom (the UK’s equivalent of America’s FCC) to investigate Rupert Murdoch’s plan to take full control of the pay-TV operator BSkyB. He’s intervened now that News Corp has formally notified the European authorities of its plans for a 100% takeover of BSkyB. Rival media groups keep complaining that would concentrate too many news outlets under one person’s control. Murdoch already owns 3 of the Britain’s biggest newspapers. Ofcom now has until the end of this year to decide whether the takeover would harm UK media plurality.

News Corp says it looks forward to discussing the takeover with the authorities now that it has delivered a 1,000-page document to Brussels-based competition regulators who will decide whether there are grounds for a deeper anti-trust investigation by December 8. Claire Enders, the media analyst who wrote to Cable back in September warning him about the impact of the Sky takeover, tells me: “We expected that this step would be taken. The law is reasonably straightforward, and the transaction always seemed to us to meet the conditions for a decision in favor of an intervention.”

Murdoch’s plans will come under concerted attack in the House of Lords today. David Puttnam will tell his fellow Lords that the buy-out would make Murdoch the most dominant media figure in any democracy in the developed world, with a greater share of the sector than even Silvio Berlusconi’s in Italy. Puttnam, who is deputy chairman of Channel 4, will tell the Lords – the UK equivalent of the Senate — that the power which News Corp would exert “is one that would not be tolerated in any other democracy, certainly not the United States”.

Cable’s fellow Coalition ministers are reportedly split over the takeover. The right-of-centre Conservatives are relaxed about Murdoch’s plan, while their Liberal Democrat partners are alarmed. Cable said: “The independent experts at Ofcom will now investigate and report to me on the media plurality issues that may arise from this proposed acquisition.”