Vicky Pryce told Southwark Crown Court that Chris Huhne made her take the speeding points in a "fait accompli" in 2003. She first revealed the offence to Sunday Times Political Editor Isabel Oakeshott in March 2011.
Pryce told the court that the revelation got Ms Oakeshott "excited" as she planned how to run the story in the newspaper. The pair agreed that the claims would be made through an interview with Pryce, and an agreement was put in place in a bid to protect her.
But Pryce told the court she was shocked to see the story on the front page, and that it included details which could reveal her as the person who took the points.
More top news
A hearing found Kirsten Treasure guilty of 'shocking' catalogue of misconduct, including refusing to respond to a manslaughter crime scene.
Showers continue across some southern and western areas tonight.
Two people are being treated in hospital after an "explosion" in a flat in West Dunbartonshire.