Isabel Diana Colegate FRSL (10 September 1931 – 12 March 2023) was a British author and literary agent.
Born in Paddington in London, England, Colegate was the youngest of her parents' four daughters.
[1] Her father was Sir Arthur Colegate, while her mother was Winifred Mary, a daughter of Sir William Worsley, 3rd Baronet, and the widow of Captain Francis Percy Campbell Pemberton of the 2nd Life Guards, who had been killed in action in the First World War.
[2] Colegate was a first cousin of Katharine, Duchess of Kent, who is also a granddaughter of Sir William Worsley, 3rd Baronet.
In 1952, Colegate, in partnership with Anthony Blond, set up the publishing firm, Anthony Blond (London) Ltd.[3] Colegate's novel The Shooting Party (1980) was adapted as an award-winning film of the same name, released in 1985 by Castle Hill Productions Inc.