Whitehall is braced for a potential cabinet reshuffle ahead of the announcement on whether Chris Huhne will be charged over allegations that his former wife accepted speeding points on her driving licence on his behalf.
The energy secretary and senior colleagues will not be told of the decision until about an hour before the announcement by Keir Starmer, director of public prosecutions, at 10am on Friday. The energy secretary has denied the allegations.
Sir Jeremy Heywood, cabinet secretary, is understood to have advised David Cameron that Mr Huhne would have to step down if the Crown Prosecution Service pressed charges against him.
This would force a reshuffle by the prime minister, who has generally resisted the idea of wholesale shake-ups of his frontbench team on the basis that they make for inefficient government.
The last departure from the cabinet, by Liam Fox when defence secretary, led to only minimal changes at the top of government, with Philip Hammond taking his place and Justine Greening becoming the new transport secretary.
Whatever the decision, it will be a watershed for Mr Huhne, Liberal Democrat MP for Eastleigh, who once stood for the party leadership against Nick Clegg.
Mr Huhne is seen as a deeply tribal politician who has made many enemies among his Tory colleagues, not least because of his headstrong criticisms during the campaign for the alternative vote. Yet as one of the Lib Dems’ most capable politicians, he is among just five members of the party to sit in the cabinet.
The police began an investigation into the speeding allegations last summer after claims that Vicky Pryce, Mr Huhne’s ex-wife, had accepted speeding penalty points on his behalf following an incident in 2003.
The alleged speeding offence was said to have taken place when Mr Huhne, then an MEP, was driving from Stansted airport after flying back from the European parliament.
It has been reported that Essex police had recommended both individuals should be charged in the files they passed to the CPS. Potential charges could include speeding and perverting the course of justice.
The legal proceedings have been delayed while the police sought to obtain evidence held by The Sunday Times, which broke the story of the original allegations. The newspaper has recently handed over details of relevant emails.
Mr Huhne has said he welcomed the investigation, as it would “draw a line under the matter”.
Mr Clegg told the BBC last month that Mr Huhne had made it “crystal clear” to him that he denied any wrongdoing.
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