A barrister and part-time judge lied to police about her role in exposing Chris Huhne's speeding points scandal, then tried to cover up her dishonesty using altered and fake documents, a court has heard.
Constance Briscoe was "intent" on bringing about the downfall of the disgraced Cabinet minister and did not baulk at lying to police in the process, Southwark Crown Court heard.
The barrister, who the court heard has "dozens of years experience", is accused of trying to pervert the course of justice by lying to police about how she helped the former energy secretary's ex-wife Vicky Pryce reveal his wrongdoing to the press.
She is also accused of altering a witness statement, then also submitting fake evidence to her solicitors and the court to cover-up her own dishonesty.
The 56-year-old, who has been suspended since her arrest in October 2012, denies three counts of intending to pervert the course of public justice.
The first alleges that, between May 16, 2011, and October 6, 2012, she provided police with two inaccurate statements, and the second that on October 6, 2012, she produced an altered copy of a statement, but claimed it was the correct version.
A third charge alleges that between October 5, 2012, and October 8, 2013, the barrister got an expert to say the alteration in her statement was due to a printer malfunction, but deliberately handed him the wrong document to look at so she could get get evidence in her favour.
Opening the case, prosecutor Bobbie Cheema QC said Briscoe had helped economist Pryce, who was a friend and neighbour of hers, to reveal information about the points-swapping scandal to newspapers after she and Huhne separated in 2010.
When police questioned her, she claimed an angry Pryce confided in her in 2003 after she found out Huhne had nominated her to take his speeding points.
The incident, described today as a "tiny snowball of deception" that caused a "mighty avalanche", led to Huhne's resignation as a cabinet minister and the subsequent prosecution and prison sentences for both him and his ex-wife.
In a witness statement to police after the story was published in May 2011, Briscoe described how she had known the couple since she moved to a few doors down in Crescent Grove, Clapham, London.
She said: "I became what I would term as an associate of theirs," adding: "I found Chris to be more easygoing than her, she is more hot tempered, what I would call a Greek temper.
"However I had never had a problem with either of them. I held both of them in the same regard."
She described Pryce confiding in her in May 2003 about Huhne nominating her as the driver of his car when he was caught speeding, and said she had told the economist her then husband should "come clean".
Miss Cheema told the jury: "On the face of it this appeared to be a statement from an independent witness, somebody who is not a close friend of either of the two people, somebody who said in terms that she held them in the same regard, somebody who was a neighbour to Ms Pryce who had been turned to in a moment of crisis but who otherwise was not close to her."
The prosecutor told the court: "Ms Briscoe presented herself, as you will see from her statements, as somebody who was quite independent and objective in her evidence, rather than someone who was involved with the media and who it appears was quite intent on Mr Huhne's downfall herself."
In a second statement to police, Briscoe denied having any contact with journalists or newspapers about the story, and maintained she was not a close friend of Pryce's but had just advised her on her divorce.
But emails obtained by court order during the Huhne-Pryce trial showed that she had advised Pryce about a contract with the Sunday Times, and was also involved in speaking to the Mail on Sunday about the story.
The court heard that between January 1, 2011 and October 2, 2012, Pryce was the sixth most contacted number by Briscoe's mobile phone, and between October 4, 2011 and October 2, 2012, was 10th among the numbers most often contacted by the lawyer's mobile.
In email exchanges between journalists, the barrister was described by one as "determined to go for the kill" and wanting Huhne to get his "comeuppance".
Miss Cheema told the jury that most striking in the exchanges was Briscoe's "apparent intent" to bring the then Cabinet minister down.
Once her involvement was revealed, Briscoe was dropped as a witness in Huhne and Pryce's trial and was arrested in October last year.
When she was interviewed by police she pointed out an alteration in one of her statements, claiming it changed the meaning - a change the prosecution claim Briscoe made herself.
In June last year, the lawyer was charged with two counts of intending to pervert the course of justice, relating to lying to police, and then to altering her witness statement.
As preparations for her own trial were under way, the court heard that Briscoe's solicitors obtained a report from an expert witness who said the alteration in the statement had actually been caused by a malfunctioning printer.
But when a prosecution expert examined the document, she found that it was not the same document at all, and Briscoe had allegedly handed him a different one so his evidence would be in her favour.
Miss Cheema said: "As you will see from the defendant's statement, the defendant is someone who knows the criminal justice system well.
"She is a professional lawyer, indeed she is a practising criminal barrister with dozens of years experience.
"As you will discover as well from the literature in the case, at the relevant time she was also sometimes sitting as a part-time judge in criminal and other cases.
She added: "Despite all her advantages, for reasons of her own she was prepared to lie to police in the Huhne-Pryce investigation, she was prepared to present an entirely false picture of herself, of her relationship with Ms Pryce and her relationship with journalists.
"And we say subsequently she was prepared to alter a statement that was presented to police and she did not baulk at obtaining expert evidence based on a lie."
Ms Cheema said: "There is no law of course that prevents Miss Briscoe assisting her friend to do damage to her husband if that's what she chose to do.
"But the criminal offences she is charged with all arise not out of that but out of what the prosecution say is Ms Briscoe acting deliberately: a) to hide what she was really up to when the police asked her about it; b) giving the police misleading information and; c) later on trying to manipulate both the police and the court during an investigation into Ms Briscoe's own actions."
The case, at Southwark Crown Court, was adjourned to 10am tomorrow when the prosecution opening will continue.