Chris Huhne faces a jail sentence after pleading guilty to perverting the course of justice.
Huhne, who was narrowly beaten by Nick Clegg in the Liberal Democrats’ leadership contest five years ago, had repeatedly denied the accusations both in public and in court.
In recent days his lawyers had also mounted a legal challenge to try and prevent the case going ahead but those pleas were rejected, leading to his surprise guilty plea yesterday.
Outside Southwark Crown Court after the hearing, Huhne said: “Having taken responsibility for something that happened 10 years ago, the only proper course of action for me is to resign my Eastleigh [Hants] seat in Parliament, which I will do shortly.”
Mr Clegg said he was “shocked and saddened” by the admission from the former Energy Secretary and a man who was being tipped again as a future leader of the Liberal Democrats before he was charged.
Huhne will be sentenced at a later date and judge Mr Justice Sweeney warned him “you should have no illusions whatsoever as to the sort of sentence that you are likely to receive”.
His decision to stand down as an MP will trigger a by-election in a constituency where the Liberal Democrats had a majority of just 3,800 at the last General Election.
The case centred on a speeding offence by Mr Huhne in 2003 but the allegation he asked his then wife to take the blame only emerged after their acrimonious divorce. Vicky Pryce has denied perverting the course of justice and her trial is due to begin today.