Former energy secretary Chris Huhne is facing a prison sentence after pleading guilty to perverting the course of justice over claims that his ex-wife took speeding points for him.
Huhne previously denied the charge and was due to stand trial alongside former wife Vicky Pryce, but dramatically changed his plea before the start of the trial at London's Southwark Crown Court.
The 58-year-old, from Dutton Lane, Eastleigh, Hampshire, denied the charge in court last week but, when asked again on Monday, clearly said "Guilty".
Perverting the course of justice often carries a custodial sentence, with a maximum term of up to life imprisonment.
Pryce previously pleaded not guilty to a charge of perverting the course of justice between March 12 2003 and May 21 2003 on the grounds of marital coercion. She is accused of falsely taking speeding points for her ex-husband.
It had been alleged that the former energy secretary, who stood down from the Cabinet after he was charged last year, persuaded the 60-year-old economist to take the points so he could avoid prosecution.
He remained the Liberal Democrat MP for Eastleigh but it is thought he may step down following his change of plea.
The events which led to the charges date back to March 2003 when Huhne's car was allegedly caught by a speed camera on the motorway between Stansted airport in Essex and London.
The allegations emerged in 2011 after Huhne's 26-year marriage to Pryce ended when he admitted an affair with PR adviser Carina Trimingham, who was in the public gallery in court on Monday.
Granting Huhne unconditional bail until a sentence date to be fixed, Mr Justice Sweeney told him: "I will deal with your sentence on a date to be notified. It is essential that you attend, obviously, on that date. As Mr Kelsey-Fry (Huhne's barrister) has foreshadowed, you should have no illusions whatsoever as to the sort of sentence that you are likely to receive."