Chris Huhne will learn on Friday morning if he will face charges for allegedly asking his ex-wife to take speeding points on his behalf.
The energy and climate change secretary has been accused of avoiding a driving ban in 2003 by getting Vicky Pryce, his then wife, to claim she had been at the wheel of the car.
Keir Starmer, the Director of Public Prosecutions, is expected to announce whether Huhne will be charged at 10am on Friday morning.
It is believed that if he is charged he may have to step down from the Cabinet and fight the allegations from the back benches.
Huhne's resignation would result in a rare cabinet reshuffle, with senior Lib Dems Jeremy Browne, a Foreign Office minister, or Ed Davey, employment relations minister, tipped for promotion.
The announcement from the Crown Prosecution Service comes after the Sunday Times dropped its challenge to a court ruling ordering evidence to be disclosed last Friday.
The material is believed to include email exchanges between the broadsheet's political editor Isabel Oakeshott and Pryce.
Essex police have been looking into the alleged incident, which occurred when Huhne was an MEP, for months.
Huhne has repeatedly denied any wrongdoing and said he hoped the investigation would "draw a line under the matter".
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