A barrister and part-time judge is being investigated by police for allegedly lying about her involvement in leaking the Chris Huhne speeding points story to the press, a court has heard.
Constance Briscoe, a friend of Vicky Pryce, was arrested after telling police she had not been in contact with the media about the story, when it later appeared that she had, Pryce's retrial heard.
Pryce, 60, denies perverting the course of justice, claiming Huhne coerced her into taking three points for him in 2003.
Last week a jury failed to reach a verdict in Pryce's trial, prompting a retrial at Southwark Crown Court which started on Monday.
The court has heard Pryce, helped by Briscoe, told journalists about the story to get revenge on Huhne after he left her for PR adviser Carina Trimingham in June 2010.
Prosecutor Andrew Edis QC read jurors a statement from Detective Inspector Martin Passmore explaining why certain people had not been called as witnesses in the case.
"Ms Briscoe has provided statements to the police in this case but during the investigation it became apparent that she may have lied about her involvement with the press and that she denied having any contact with the Mail on Sunday or any other media organisation in relation to this story," his statement said.
"Ms Pryce has not been arrested or interviewed in relation to that allegation.
"For this reason Ms Briscoe has been arrested and is currently under investigation by the police. Ms Briscoe could therefore no longer be relied upon as a witness of truth and on October 2, 2012 the Crown Prosecution Service took the decision not to call Ms Briscoe to give evidence in the case."
Former energy minister Chris Huhne pleaded guilty to perverting the course of justice and resigned as MP for Eastleigh at the start of the first trial and will be sentenced once this trial is over.