Chris Huhne: The affair, the phone call, and how it all went wrong for the millionaire minister

Andy McSmith charts his dazzling rise in the City and Westminster – and a speedy fall

Huhne's former press secretary Carina Trimingham (Reuters)

Vicky Pryce was not cut out to be the tame little wronged wife hiding from the public eye after the humiliation of having her husband leave her for another woman. She did manage to keep her feelings to herself for 11 months, before deciding it was time to tell her story and show her ex-husband up as a man who could not be trusted.

She intended to damage his reputation, and possibly to put the brakes on his political career. She may have anticipated there would be some personal cost to herself, but she cannot, surely, have foreseen that she would find herself in court with her ex, facing a serious criminal charge.

Their 26-year marriage was a union of two bright, hard-working high-flyers. Before their acrimonious separation, she and her husband would play host each winter to a shindig for about 200 guests at their three-storey town house in Clapham, south London. After their break-up, it was held again, as usual, with the nation's top civil servant, Sir Gus O'Donnell, and the former Labour Lord Chancellor Charlie Falconer among the guests. Only this time, Chris Huhne was absent.

When they first met, he was an economics journalist and she was a successful businesswoman who had risen to be chief economist for Williams & Glyn's bank before moving to KPMG. Born in 1952 as Vasiliki Courmouzis, in Athens, to Greek parents, she took the surname Pryce from her first marriage, by which she had two children. She was to have three more by Chris Huhne, without taking a career break.

Her independent income helped him to leave journalism, set himself up in the City and become a millionaire before he went into full-time politics. She too harboured an ambition to be a Liberal Democrat MP, which she probably could have been, because she was popular in the party, had a good working relationship with Vince Cable and an impressive CV.

In 2002, she moved from the private sector into the civil service, as the first woman to hold the post of Chief Economic Adviser at the Department of Trade and Industry, later the Department for Business. On election night, 6 May 2010, the couple stood side by side, posing for the cameras, as Mr Huhne was re-elected MP for Eastleigh. That night, Ms Pryce had no inkling that their life together was about to collapse.

The bombshell came six weeks later, on a Saturday afternoon, when she was watching a World Cup football match on television and heard the phone ring in another room. At half-time, she went to get something to eat, and her shaken husband came in to say that the call was from the News of the World, which had been on the trail of the newly appointed Secretary of State for Energy. The newspaper had proof that he had spent the previous night in his constituency home in Eastleigh with the former journalist Carina Trimingham, who had been his press secretary when he was running against Nick Clegg for the Liberal Democrat leadership. He told his shocked wife they had "30 minutes to kill the story" – a phrase she later thought of using as a book title.

"In a few minutes I learnt that our marriage had come to an end. He went to the study and wrote the statement, and then went to the gym. That was that," she later told the BBC. That afternoon, Mr Huhne released a terse press statement saying: "I am in a serious relationship with Carina Trimingham and I am separating from my wife." This set off what must have been an excruciatingly humiliating round of media exposure, much of which focused on Ms Trimingham's personal life.

One story was about Mr Huhne's driving. It was known he had once been banned from driving for three months for using a phone at the wheel. An inaccurate rumour circulated he had been caught speeding when an MEP, but had avoided another ban by persuading "a female constituency aide" to take the points on her licence. His office dismissed the claim as "completely untrue".

For months, Ms Pryce, who had her children and career to think of, bore all this humiliation in silence – in public at least. Then in May 2011, a whole year after the general election, she gave an interview to a Sunday newspaper about the final days of her marriage.

During that interview, she was asked about that old rumour about the speeding offence. She could have denied it, or said she knew nothing about it, but she was either too angry or too honest, and she started a chain of events that brought her ex-husband's political career to a halt. The couple will meet again in Westminster Magistrates Court.

Charge: Perverting the course of justice

A disqualification from driving for amassing 12 penalty points on your licence is infinitely preferable to being convicted of perverting the course of justice under the common law.

The latter carries a maximum life sentence and a fine, although such a prolonged incarceration is highly unlikely. Even Karen Matthews, who kidnapped her own daughter Shannon to claim reward money, was jailed for eight years for perverting the course of justice in conjunction with other offences.

Last year, a Bournemouth man was jailed for eight weeks after he falsely claimed he wasn't behind the wheel when a car was caught speeding on four separate occasions.

Fabricating or disposing of evidence, threatening or intimidating a witness, juror or judge can all constitute perverting the course of justice, although a positive act is required to warrant the charge: you can't be tried for simple inaction.

The Conservative MPs Jeffrey Archer and Jonathan Aitken were both jailed for perjury and perverting the course of justice.

The two offences are often confused. Perjury, or lying under oath – not one of the charges levelled at Mr Huhne – is a statutory offence under the Perjury Act 1911.

According to a poll of 2,000 drivers last year, 3 per cent of male drivers are guilty of point-swapping. The person who receives the penalty on their behalf can also be charged with perverting the course of justice.