Early life
She was born in Rhyl, Flintshire, Wales, the younger child of an Anglican clergyman, who had lost his faith and used the parish magazine to celebrate the Soviet persecution of the Russian church. He also sexually abused her. Her father frequently changed his parish, so, consequently, she attended numerous schools. She left University College, London, after only one year.
Adulthood
She married Charles Dimont, a journalist, in 1937, and they had two daughters, including the actress Caroline Mortimer, and two daughters through extra-marital relationships with Kenneth Harrison and Randall Swingler.
She met barrister and writer John Mortimer while pregnant with the last child and married him in 1949. Together they had a daughter and a son.
She had one novel, Johanna, published under her name, Penelope Dimont, then as Penelope Mortimer, she authored A Villa in Summer (1954; Michael Joseph). It received critical acclaim. More novels followed.
She was also a freelance journalist, whose work appeared regularly in The New Yorker. As an agony aunt for the Daily Mail, she wrote under the nom de plume Ann Temple. In the late 1960s, she replaced Penelope Gilliatt as film critic for The Observer.
Her marriage to John Mortimer was difficult. They both had frequent extramarital affairs. Penelope had six children by four different men. They divorced in 1971. Her relationships with men were the inspiration for the novels, Daddy's Gone A-Hunting (1958; republished in 2008 by Persephone Books) and The Pumpkin Eater (1962; reissued in 2011 by New York Review Books), which was adapted for the screen by Harold Pinter. It starred Peter Finch, James Mason and Anne Bancroft, who won an Oscar nomination for her role.
Mortimer continued in journalism, mainly for The Sunday Times, and also wrote screenplays. Her biography of the Queen Mother was commissioned by Macmillan, but when completed, it was rejected so instead Viking published it in 1986. Her former agent Giles Gordon in his Guardian obituary called it "the most astute biography of a royal since Lytton Strachey was at work. Penelope had approached her subject as somebody in the public eye, whose career might as well be recorded as if she were a normal human being."
She wrote two volumes of autobiography, About Time: An Aspect of Autobiography, covering her life until 1939, appeared in 1979 and won the Whitbread Prize, and About Time Too: 1940–78 in 1993. A third volume, Closing Time, is unpublished.
She died from cancer, aged 81, in Kensington, London, England.
Novels
Johanna (1947) (as Penelope Dimont)
A Villa in Summer (1954)
The Bright Prison (1956)
Daddy's Gone A-Hunting (1958)
The Pumpkin Eater (1962)
My Friend Says It's Bulletproof (1968)
The Home (1971)
Long Distance (1974)
The Handyman (1983)
Short story collections
Saturday Lunch with the Brownings (1977)
Humphrey's Mother
Autobiographies
About Time: An Aspect of Autobiography (1979)
About Time Too: 1940–78 (1993)
Biography
Queen Elizabeth the Queen Mother (1986), revised edition published in 1995, subtitled An Alternative Portrait Of Her Life And Times
Travel writing
With Love and Lizards (co-authored with John Mortimer, 1957)