Chris Huhne and his ex-wife Vicky Pryce are both facing jail after she was convicted of perverting the course of justice by taking speeding points for him a decade ago.
Pryce, 60, was found guilty today after a retrial at Southwark Crown Court, while former energy secretary Huhne admitted the offence last month at the start of their trial.
A date for sentence has not yet been set, but the former couple have both been warned by Mr Justice Sweeney to be under no illusion of what to expect.
Perverting the course of justice carries a maximum sentence of life imprisonment, with the average jail term at 10 months.
Huhne, 58, also faces a hefty legal bill after lengthy attempts to get his case dismissed, as the Crown Prosecution Service (CPS) announced it will apply for costs.
Malcolm McHaffie, deputy head of special crime at the CPS, said: "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."
Pryce, of Crescent Grove, Clapham, south London, looked shocked as the jury of seven men and five women returned a guilty verdict today after deliberating for more than 12 hours.
Giving a statement outside court as the economist faced crowds of waiting media, her solicitor Robert Brown said: "Mrs Pryce is naturally very disappointed to have been convicted.
"She would like to thank all those who have supported her during this difficult process, particularly her children, her friends and colleagues.
"Mrs Pryce will return to court to be sentenced in due course. No further comment will be made until this is completed."
The verdict brings the long-running scandal to an end, a decade after Pryce took speeding points for her then husband as he tried to avoid losing his driving licence.
The offence only came to light in May 2011 in the national press after a media campaign by Pryce - disclosed during the trial - to "nail" her former husband after he left her for PR adviser Carina Trimingham.
Huhne staunchly denied the allegation but was forced to step down as a Cabinet minister after he and Pryce were charged last February.
His attempts to fight the case failed and he dramatically changed his plea to guilty on the first day of his trial, resigning as MP for Eastleigh and bringing an end to a once-promising political career.
In further political fallout, business secretary Vince Cable and Nick Clegg's wife Miriam today denied they knew anything of the scandal before it hit the headlines, after questions were raised about how much the Lib Dems knew before the story was published.
Emails between Pryce and Sunday Times political editor Isabel Oakeshott, disclosed to the jury, suggested that Pryce had confided in Mr Cable and his wife Rachel about the points swapping.
The high-profile case saw mother-of-five Pryce stand trial twice after a jury in her original proceedings failed to reach a verdict.
She adopted the defence of marital coercion during her trial, claiming he had forced her to take the points against her will.
She claimed she was constantly forced to sacrifice her own career in favour of his, and disclosed in court that he twice tried to persuade her to have an abortion - saying she acquiesced once then refused a second time.
The court heard Pryce was helped in her dealings with the press by barrister and part-time judge Constance Briscoe - who has since been arrested for allegedly lying to police.
Briscoe, 55, who was dropped as a prosecution witness in Pryce's case, could now find herself facing trial after email evidence showed her claims to detectives that she had not spoken to journalists about the story were untrue.
In a statement after today's verdict, assistant chief constable Gary Beautridge, from the Kent and Essex Serious Crime Directorate, which investigated the offence, said: "The conviction of Chris Huhne and Vicky Pryce has been achieved through the thorough and steadfast investigation conducted by officers and specialist staff at Essex and Kent Police.
"Perverting the course of justice is a serious offence. 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."