Pryce had pleaded not guilty to obstructing justice for taking the fall for a speeding penalty for her then-husband, Chris Huhne, in 2003. She claims she was coerced by her husband into taking the license penalty points for his speeding offense.
Huhne who had repeatedly denied wrongdoing entered a last-minute guilty plea to the same charge just before his trial was due to start earlier this month. The case shattered his political career: he resigned as a UK lawmaker the same day he pleaded guilty.
Pryce, an economist who has worked as a senior adviser in both the private sector and in government, will now face a retrial.
The details of her case riveted Britain, as deeply personal and embarrassing revelations about the powerful couple's 25-year marriage emerged.
Pryce and Huhne split in 2010 after it was revealed that he was having an affair with his public relations adviser.
