Bullying right-wing media bosses invaded the Independent’s offices after the newspaper attacked David Cameron’s backroom deal with US-based mogul Rupert Murdoch.

The Aussie-born billionaire’s son James and flame-haired sidekick Rebekah Brooks strode into the newsroom brandishing the paper with the headline Rupert Murdoch Won’t Decide The Election – You Will.

The wild-eyed duo then started to harangue bemused editor Simon Kelner in a foul-mouthed tirade.

Murdoch Jnr, 37, who runs Sky TV and his dad’s right-wing papers The Sun and The Times, accused Kelner of “impugning our family name” and shouted: “you’re a f****** f***wit.”

The crazed duo then threatened to “expose” the Independent’s owner, ex-KGB agent Alexander Lebedev.

They also ranted about online Indie ads which said: “A few people count too much. Rupert Murdoch controls 40% of the Press in Britain. On May 6 he will throw the weight of the country’s two biggest newspapers behind one party.”

Ironically, PR outfit Freud Communications, whose portly owner Matthew Freud is married to Murdoch Jnr’s sister Lis, has been advising the Independent.

One Independent source said yesterday: “They were in full fingerjabbing mode and virtually frothing at the mouth. None of us had seen anything like it. And bearing in mind the number of people they have impugned over the years, it was a little rich to say the least.

"The mini mogul is happy for his scandal sheets to dish out criticism, but can’t take it himself. He lost all control.”

Rupert Murdoch, 79, agreed to support Mr Cameron last September on the condition he dismantles parts of the BBC and scraps TV watchdog Ofcom if he reaches No10.

But from the moment he endorsed Mr Cameron the Tory leader’s fortunes have plummeted.

Senior Tory Boris Johnson told friends yesterday he had been told by senior Murdoch executives that their decision to back Cameron had been “a complete disaster”.

Tory grandees also blame the Murdoch factor for turning people off their leader. And so desperate are the Murdochs to shore up their candidate, they have run a series of laughable character assassinations of Lib Dem leader Nick Clegg in The Sun.