Marie Christine Chilver, known as Christine, (12 September 1920– 5 November 2007) (Latvian: Marija Kristine Cilvere), also known by the codename Agent Fifi, was a British secret agent in World War II.
Originally recruited after escaping the Nazis and helping a British airman return to England, she worked for the Special Operations Executive (SOE) assessing and testing the security awareness of trainee secret agents.