She denies the charge and has adopted a defence of marital coercion, saying Huhne persuaded her to take the points.

Prosecutor Andrew Edis, QC, told the jury at Southwark Crown Court in London the points-swapping only came to light in 2010/2011 when Pryce told several newspapers in a bid to ruin her former husband's career after he left her for his former press adviser Carina Trimingham.

The jury was yesterday read emails between Pryce and Sunday Times political editor Isabel Oakeshott – who is due to appear as a prosecution witness tomorrow – in which they discussed how the story could be published and end Huhne's career. They also heard four calls Pryce made to Huhne around April 2011, which were recorded with Ms Oakeshott's help in an unsuccessful bid to get some proof for the story.

Mr Edis told the jury they would have to decide whether Pryce, an economist and senior civil servant, was "weak-minded" and forced by Huhne into accepting the points, or was a "strong-minded and manipulative" woman acting of her own free will. "Focus not on whether she was persuaded but whether she was in a situation where she had a choice," he said.

He added: "Her revenge in the end was to pass the story of the 2003 points to the newspaper so they would publish it and destroy his political career."

In the email exchange from March 1, 2011, Ms Oakeshott suggested a number of pieces run in the Sunday Times including news features and a story at the front of the paper, writing: "This is what I strongly recommend you do, given your dual objectives of bringing Chris down, if you can, without seriously damaging your own reputation in the process."

In a later email she warned Pryce of the danger of facing criminal proceedings if she did reveal she took his penalty points, and that the newspaper was discussing the issue.

Pryce wrote: "I would need some reassurance it would bring Chris down."

Later she added: "I have no doubt, as I really want to nail him. More than ever actually, and I would love to do it soon."

Ms Oakeshott later replied: "The bottom line is that this story will bring Chris down if you are prepared to go on the record, with the minor risk this carries. I think you can make yourself out to be very much the honourable one, saying it has very much been on your conscience ever since, saying you knew it was wrong but you were bullied into it."

During four phone calls played to the jury, Pryce tried to get her former husband to admit she had taken the points in 2003. She repeatedly asked Huhne to confirm she took his points, but her ex-husband staunchly denied it. At one point he told her: "Can I suggest if you want to stop journalists door-stepping you, you stop telling ridiculous stories to the press?"

In a later call he told her not to speak to Ms Oakeshott, saying: "There is no upside to talking to her from your point of view. There is only a potential downside."

Pryce's trial will continue tomorrow.

l UK Independence Party leader Nigel Farage has ruled out standing in the Eastleigh by-election. The poll has been triggered by Huhne's decision to stand down as a Liberal Democrat MP.