London One of BSkyB's biggest investors has warned that James Murdoch's exit from News International suggests he will soon also lose his position as chairman of the pay-TV broadcaster.

Murdoch's resignation from News International, the UK newspaper business that owns the Sun and The Times titles, was revealed on Wednesday, but shareholder Crispin Odey suggested it would be followed by further changes.

Odey, whose fund Odey Asset Management owns 2.7 per cent of BSkyB, has been one of Murdoch's most loyal champions.

However, he said Wednesday's move suggested Murdoch was out of favour in News Corporation and that the matter had been taken out of shareholders' hands. "This is coming from the inside, not the outside," Odey told The Daily Telegraph.

"They've switched the backing, so Lachlan [Murdoch] climbs up and James climbs down."

Asked whether Murdoch was likely to leave BSkyB as chairman, Odey said: "It's starting to feel that way … Everybody's feeling is that if he's going to New York, is his heart going to be in Sky anymore? Probably not. There is definitely change afoot. They'd have to do something pretty drastic to turn things around and I'm not sure they can."

Odey warned last autumn that James Murdoch's move to the US as deputy chief operating officer of News Corp would make him too "hands off". Media sources said the decision to turn on James Murdoch suggested the media family would be equally "ruthless" in other parts of its empire.

"It's so nasty, the Murdoch politics. Rupert is backing Lachlan and James is being sidelined. They never listen to outsiders, we're all the enemy," said one source. "They're taking action because they're embarrassed. Rupert hoped he could bring all newspapers [in the UK] into this, that it couldn't just be his journalists, but that proved incorrect and he now feels exposed."