* Jury in trial of Vicky Pryce fail to agree on verdict
* Ex-husband Chris Huhne pleaded guilty in same case
* Protracted scandal ended his political career (Adds date of retrial, details, background)
By Estelle Shirbon
LONDON, Feb 20 (Reuters) - The ex-wife of fallen British minister Chris Huhne will face a retrial for perverting the course of justice by helping him dodge a driving ban in 2003, after a jury failed to reach a verdict on Wednesday.
Huhne, once considered a likely successor to Deputy Prime Minister Nick Clegg as leader of the Liberal Democrats, pleaded guilty to the charge on Feb. 4.
Huhne has been warned to expect a prison sentence. His sentencing has been deferred until the end of the retrial of his ex-wife, Vicky Pryce, which is expected to start on Monday.
The inconclusive end of Pryce's first trial was the latest twist in a long-running scandal that toppled Huhne from his cabinet post and has gripped the British public with salacious revelations about the private lives of a once powerful couple.
The allegation against the estranged pair is that they falsely informed police that she was driving his car when it was flashed by a speed camera in March 2003. She took penalty points on her licence which, if he had taken them, would have resulted in a six-month driving ban.
The deception, which took place at a time when the couple were happily married, remained a family secret for eight years but came back to haunt Huhne after the acrimonious break-up of his 26-year marriage to Pryce.
He abruptly left her in June 2010 when his long-term affair with bisexual former aide Carina Trimingham was about to be exposed in the press. Details of the trio's private lives were splashed all over the newspapers for days.
Months later, Pryce told two newspapers about the 2003 points incident in what the prosecution at her trial described as an act of revenge against Huhne.
"I WANT TO NAIL HIM"
The jury were shown an email from Pryce to a journalist in March 2011 in which she wrote "I definitely want to nail him".
The first news reports about the points appeared in May 2011 and police then started investigating the matter, culminating in criminal charges against Huhne and Pryce in February 2012.
Huhne, who was energy secretary in the Conservative-Liberal Democrat coalition government, resigned from that post when the charges were announced.
Pryce pleaded not guilty, arguing that Huhne had used "marital coercion" to force her to take his points.
Huhne and Pryce had been supposed to stand trial together but his 11th-hour guilty plea on the morning the trial was due to start meant that Pryce was alone in the dock.
Her trial revealed intimate and painful details of the feuding couple's past. In particular, seeking to bolster her marital coercion defence by showing that in certain circumstances she could be bullied by Huhne, Pryce said he had pressured her into have an unwanted abortion in 1990.
The court also heard colourful snippets from months of discussions in 2010-2011 between Pryce and journalists keen to publish a story with the potential to bring down a minister.
In one email read in court, a Mail on Sunday journalist asked Pryce's intermediary if there was "lift-off" for an article, in the form of Pryce confirming the points story.
"If so, I suspect he will be an ex-minister by Sunday lunchtime," the journalist wrote. (editing by Stephen Addison)