The BBC reports this morning that rival media groups have come together and called on business secretary Vince Cable to consider blocking Murdoch’s planned bid for the remainder of BSkyB.

Signatories are said to include the heads of the BBC and Channel 4 and chief executives of newspapers including the Telegraph, the Guardian, the Mail and the Mirror. The letter argues that any such bid would “reduce diversity in the industry”.

In June, News Corp told the board of BSkyB that it was prepared to pay 700p a share to take full control of the leading satellite broadcaster. BSkyB’s directors said the offer was £1 per share too low, but agreed to resume negotiations after regulatory hurdles have been cleared.

News Corporation has been confident that it could demonstrate that the combination of BSkyB with News Corporations’ UK newspapers – the Sun, the Times, the News of the World and the Sunday Times – does not pose a serious threat to competition.

This follows news last month that similar calls on Vince Cable were being backed by the National Union of Journalists while founder of Enders Analysis Claire Enders wrote to Cable to voice her concerns over the future plurality of the media.