She is the daughter of political journalist Peter Jenkins and the stepdaughter of The Guardian columnist and author Polly Toynbee.
Jenkins turned to writing and in 1996 achieved her first significant success with This Life, a BBC television drama series about the lives and loves of a household of solicitors and barristers.
Other film, television and journalism work followed and in 1998 she secured a two-novel contract, her first novel, Honeymoon, appearing in 2000.
Although it was the second biggest debut novel of the year, selling over 250,000 copies in the UK and Commonwealth, critics noted that a central plot device in Jenkins' work possessed a striking similarity to the premise of Noël Coward's play Private Lives.
She has directed three short films including the "Mr Cool" segment of Tube Tales.