Former Lib Dem Cabinet minister Chris Huhne pleaded guilty to perverting the course of justice after years of denials over a simple speeding ticket.
The disgraced MP could face jail after admitting to speeding down a motorway a decade ago - and, when caught on camera, allegedly convincing his then wife Vicky Pryce to take the fall.
The former energy secretary had been expected to plead not guilty at Southwark Crown Court in London today, having repeatedly called the allegations "simply incorrect" since they emerged in 2011.
Huhne has said that he will also resign his Eastleigh seat.
Huhne made repeated attempts to have the case thrown out of court, with barrister John Kelsey-Fry telling the court the prosecution's case was circumstantial - "at best gossamer-thin."
But prosecutors said Mr Huhne had a history of speeding, with nine points on his licence already and close to losing it.
He had flown into Stansted airport less than an hour before his BMW was snapped on the M11.
Meanwhile Ms Pryce had spent the evening at the London School of Economics.
The trial continues, with both charged with perverting the course of justice.
Ms Pryce has pleaded not guilty on grounds of marital coercion.
Huhne will be best known to British National Party supporters for his arrogant attitude whilst appearing alongside Nick Griffin on the infamous Question Time show-trial.
Nick Griffin has condemned the former policing spokesman for drawing out his plea at the public's expense. Saying: "He should have pleaded guilty when he appeared before magistrates over six months ago. He should be made to pay these costs and jailed."