She is a granddaughter of Valentine Fleming, a Conservative Member of parliament who was killed during World War I in May 1917, and of his widow, Evelyn.

Amaryllis Fleming was the actress's half-aunt, fathered by Welsh painter Augustus John during his relationship with Evelyn.

"[1] Fleming is perhaps best known for her role as Jenny Richards in the BBC post-apocalyptic drama series Survivors, which originally aired from 1975 to 1977.

Her numerous credits in other British television series include The Avengers, Lydia Bennet in BBC's 1967 Pride and Prejudice series, Maud Ruthyn on the Season 4 episode "Uncle Silas" of the anthology series Mystery and Imagination, Smiley's People, Mr. Bean, the regular role of Jo in Cold Warrior, the first Helen Wycliffe in Wycliffe, A Dance to the Music of Time, Heartbeat, Rosemary & Thyme and Kingdom.

Between 2016 and 2017, she appeared on the long running radio soap opera The Archers as Miranda, who entered the series as the wife of minor tycoon Justin Elliot but subsequently reached a divorce settlement following his affair with Lilian Bellamy.