Jeremy Hunt's aide Adam Smith told to testify to Leveson over Sky bid

Jeremy Hunt's hopes of holding on to his post in the Cabinet were weakened yesterday when the Leveson Inquiry announced it has called both his former special adviser and News Corp's chief lobbyist to give evidence on how the Culture Secretary's office fed inside information to Murdoch executives during the £8bn attempted takeover of BSkyB.

Mr Hunt's former aide, Adam Smith, and the News Corp lobbyist, Fréd Michel, will appear before the judicial inquiry before the end of this month.

The unexpected announcement came as the former chief executive of News International, Rebekah Brooks, her husband, Charlie, and four others were formally charged with conspiracy to pervert the course of justice over events relating to the phone-hacking scandal. News International's former head of security, Mark Hanna, was among those charged with the conspiracy offence. Last night Ms Brooks said she could "not express strongly enough my anger that those close to me have been dragged into this".

Although David Cameron will be concerned that the Brookses, both friends, face criminal proceedings, his immediate worry will be the future of Mr Hunt.

Both Mr Smith and Mr Michel will be appearing as inquiry witnesses within the next fortnight, offering their versions of the links and insider information that was exchanged between Rupert Murdoch's company and the Government in the run-in to the controversial £8bn bid for BSkyB. They are scheduled to appear before Mr Hunt is given the opportunity to explain his role at the Royal Courts of Justice.

Emails and texts between Mr Michel and Mr Smith, published during the questioning of James Murdoch last month, led Labour to call for Mr Hunt's immediate resignation amid claims that there was overwhelming evidence of his bias towards Rupert Murdoch's company during the bidding process.

Although Mr Hunt has denied any improper conduct, Mr Smith resigned.

The House of Commons this week stated that its constitutional supremacy meant it should be given full disclosure of any evidence relating to the bid and that Parliament should be the first authority to judge Mr Hunt's conduct.

In line with his refusal to grant Mr Hunt a fast-tracked appearance at the inquiry, Lord Justice Leveson yesterday called on the Speaker, John Bercow, to back off, threatening to dump the entire BSkyB issue from his inquiry unless he was given adequate time to question Michel, Smith and Hunt ahead of Parliament.

The appeal court judge said he hoped there would be "sufficient respect" from Mr Bercow to allow the inquiry to proceed and "ensure that the principles of fairness were maintained".

Although he said he would not tell Parliament how far it should go, he said if he couldn't adduce the evidence of Mr Hunt and the BSkyB bid fairly, he would not do it at all. Last night Labour withdrew a parliamentary question calling on Mr Hunt to give evidence to the Commons first.

A political allegation that the Commons' work was being blocked, was also withdrawn by the party. Lord Justice Leveson's threat appeared to have paid off.

During the inquiry's proceedings yesterday, Sky News's political editor, Adam Boulton, said that he thought the current "lobby system" where political journalists are briefed daily by the Prime Minister's official spokesman, was "corrupt".

Mr Boulton, whose wife Anji Hunter was part of Tony Blair's Downing Street communication team, said a "White House" style of televised briefings should be brought in.