The former wife of ex-cabinet minister Chris Huhne has been found guilty of perverting the course of justice by taking speeding points on his behalf.
Vicky Pryce, 60, who had claimed Huhne had forced her to take the points over the incident on the M11 in 2003, was convicted at Southwark Crown Court.
The judge warned the pair faced jail, while the Crown Prosecution Service said it would try to recover costs.
Huhne, 58, resigned as a Liberal Democrat MP after admitting the charge.
The verdict, after 12 hours of deliberations, came in a retrial.
The jury in a trial last month failed to reach a decision, prompting the judge to question its "fundamental deficits in understanding" of their role and the trial process.
Following Thursday's verdict, Mr Justice Sweeney said sentencing of Pryce, who is from Clapham, south London, and Huhne would take place at a later date. He granted her bail until the next hearing.
"Obviously Ms Pryce was present when I indicated to Mr Huhne the inevitable consequences of a conviction for an offence of this sort," he said.
"She must be under no illusions that my granting of bail indicates any watering down of that provisional approach."
Speaking outside the court, Pryce's solicitor Robert Brown said she was "naturally very disappointed to be convicted".
He said she would not be making any further comment until after sentencing takes place.
The CPS is understood to have run up about £100,000 in costs after Huhne attempted to have the prosecution against him thrown out before the trial began.
"Chris Huhne made sustained challenges against the prosecution before pleading guilty at the last minute. This was expensive for the CPS and we will be applying for costs," said CPS lawyer, Malcolm McHaffie.
The pair were charged last year over an incident in March 2003 when Huhne's BMW car was caught by a speed camera on the M11 motorway between Stansted Airport, in Essex, and London. He was an MEP at the time.
It was alleged that between 12 March and 21 May 2003, Pryce, a prominent economist, had falsely informed police she had been the driver of the car, so Huhne, who went on to become the MP for Eastleigh, in Hampshire, would avoid prosecution.
He was in danger of losing his licence having already accrued nine penalty points.
After the verdict, Assistant Chief Constable Gary Beautridge, said: "We hope this conviction serves as a timely reminder to motorists who try and avoid driving bans by 'giving' their points to others.
"This practice is not only unlawful, but has life-changing consequences for those who get caught flouting the rules."
During both trials, Pryce accepted she had taken Huhne's points, but adopted a defence of marital coercion, claiming he had made her sign a form he had already completed in her name.
However, the prosecution alleged Pryce had chosen to take the points, but later plotted to expose Huhne after he revealed he was having an affair with an aide and ended the couple's 26-year marriage.
Prosecutor Andrew Edis QC told the jury the end of Ms Pryce's marriage was "distressing, very upsetting" but "being the person that she is, a strong-minded, strong-willed person, it also caused her great anger and in the end led her to want to get revenge".
He said the pair had "cheated the system" over responsibility for the speeding incident.
Rejecting Pryce's defence of marital coercion, Mr Edis said she was a "woman who had spent her life making important choices... and here she is saying that she was unable to choose whether to commit a crime or not because a man, whether her husband or not, was telling her what she had to do".
The court was told Pryce later told Sunday Times journalist Isabel Oakeshott what the couple had done and was persuaded that a carefully written story could expose the politician.
Pryce said in an email to Ms Oakeshott: "I definitely want to nail him. More than ever, I would love to do it soon."
She also recorded some of her phone calls with Huhne in a failed attempt to get the then MP to incriminate himself.