Vince Cable told undercover reporters he had "declared war on Rupert Murdoch" and planned to block his efforts to take full control of BSkyB, according to the BBC's Robert Peston.

The business secretary's admission came in a conversation with Daily Telegraph reporters posing as constituents.

The BBC's Robert Peston said the Telegraph chose not to publish the "most explosive" part of its investigation.

But a transcript was passed to him by a whistleblower.