The final act: Chris Huhne and Vicky Pryce sentenced to eight months

Chris Huhne and Vicky Pryce were both sentenced to eight months in prison today, in a catastrophic ending to a high-flying political career.

Mr Justice Sweeney said the pair were "acting together" when they decided to pervert the course of justice by pretending she was driving a car found to have been speeding.

"No doubt you thought you would get away with it," he said.

He told the couple they acted out of "shared ambition" for Huhne's continued political career and their desire not to suffer the inconvenience of him losing his licence.

After the marriage broke up, Pryce had an "implacable" desire for revenge despite the consequences to her wider family, he found. But her decision to use the press as her "weapon of choice" was dangerous, because it had been a joint offence.

Pryce "sought to manipulate and control the press so as to achieve [her] dual objective" of bringing down Huhne and not implicating herself, Mr Justice Sweeney continued.

He told the defendant she had a "controlling, manipulative and devious side" to her character.

Turning his attention back to Huhne, the judge said: "Despite your high office you tried to lie your way out of trouble by claiming you were innocent."

He added: "To the extent that anything good has come out of this it is that now finally you have both been brought to justice.

"You have fallen from a great height".

Huhne got a ten per cent reduction in his sentence for pleading guilty.

The former energy secretary, dressed in a dark suit and tie with a white shirt, walked past his former wife as they sat less than four feet apart, with an empty chair separating them in the dock.

There was no sign of recognition or acknowledgement between the pair. Both looked down solemnly for long periods as arguments about sentencing were read out.

Prosecutors told the judge Huhne had shown "highly selective amnesia in interviews, which the jury would have been invited to consider was not an honest stance".

Huhne's barrister, John Kelsey-Fry, apologised on behalf of his client to constituents, colleagues and the court.

"Nobody has ever lost more so publicly and suffered such vilification for an offence of perverting course of justice by point swapping," Kelsey-Fry said.

Explaining why Huhne had been so slow to admit his guilt, he added: "In human terms there is a natural instinct against meekly handing your assailant what she has sought."

The QC also insisted Huhne had not forced, bullied or coerced Pryce into taking the points. The judge accepted that argument, saying the two trials of her defence of 'marital coercion' satisfied him that she did not need much persuasion.

His lawyer said Huhne strenuously rejected claims made during her trial that he forced her into having an abortion. The judge said he did not take those arguments into account in sentencing.

"I am sorry," Huhne told the Guardian hours before sentencing.

"I want to say that to family, to friends, to constituents and to colleagues, and more broadly to everybody who cares passionately about the causes I care about, including saving the planet for our children and our grandchildren.

"I have to accept responsibility, and I should not have asked my ex-wife to take my speeding points, and I should not have lied on an official form, and I should not have tried to evade the consequences.

"I want, and have, to say sorry for not owning up when the story first came out. I should have owned up and got on with doing something else with my career. Lawmakers can be many things, but they cannot be lawbreakers."

The sentence marks the end of a political career which nearly saw Huhne become Liberal Democrat leader – and possibly deputy prime minister.

The confident political operator won praise for his vociferous defence of civil liberties in opposition and then as energy secretary in the coalition.

He is sorely missed by many Lib Dem colleagues as one of the party's few figures around the Cabinet table who was prepared to take the fight to the Conservatives, especially during the AV referendum.

Nick Clegg has found it easy to be charitable to his former leadership rival. He told a fringe event at the party's spring conference in Brighton this weakened that he viewed Huhne as "a very effective secretary of state" and an "extremely powerful thinker".

The man himself was said to be in positive spirits ahead of today's sentencing at Southwark crown court in London.

"Chris is amazingly chipper," a source close to Huhne told the Mirror on Sunday.

"He thinks it will all blow over and if he goes to prison he will be out in no time. He's talking of being out in six weeks."

Pryce's custodial sentence is the final dramatic twist in a story of jealousy, betrayal and revenge which has gripped Westminster.

Her attempt to end Huhne's career by revealing his demand that she take his speeding points came after he left her for his aide Carina Trimingham.

Pryce had written in an email to Sunday Times journalist Isabel Oakeshott: "I just want the story out there so he has to resign."

Oakeshott told the BBC's Sunday Politics programme she viewed Pryce as a "broken woman".

"There are two sides to her personality," she explained. "There was the one that was very emotional, and then there's the other that was very rational, and she was very clear what she was doing."

Pryce reportedly spent Sunday buying a radio to listen to while behind bars.

Huhne's decision to step down to "clear his name" was the first time in British history a minister had been forced to quit the Cabinet to answer criminal charges.

He is the first former-Cabinet minister to go to be imprisoned since Jonathan Aitken was jailed for perjury in 1999.

Aitken told the Today programme that Huhne would find life in jail "disorientating and tough but not terrible".

He explained: "It's all a pretty wild west scene for someone that is used to the relative calm of Westminster."

It continues a nightmare period for the Lib Dems, which is probing allegations of sexual harassment against former chief executive Chris Rennard and broader cultural problems within the party.

The party is also facing a growing unrest in its own ranks over its plan to introduce secret courts and a snoopers' charter.