Peter Grenfell, 2nd Baron St Just

Grenfell was the only son of Edward Grenfell, a partner in Morgan, Grenfell & Co., director of the Bank of England, and Member of Parliament for the City of London, and his wife Florence Emily Henderson.[1] He was educated at Harrow School.[2] In July 1935, while he was still there, his father was raised to the peerage as Baron St Just, of St Just in Penwith in the County of Cornwall.[3]

During the Second World War, Grenfell was commissioned as a Lieutenant into the King's Royal Rifle Corps. On 26 November 1941, his father died and he succeeded as Lord St Just,[1] but could not take his seat in the House of Lords until reaching the age of twenty-one two years later.

Wilbury House

On 1 June 1949, at St James's, Spanish Place, St Just married Leslie Nast, daughter of Condé Nast and Leslie Foster.[4][1] They were divorced in 1955, and on 25 July 1956 he married secondly Maria Britneva,[1] an actress, the daughter of Alexander Britnev, whose mother had brought her to England as a child.[5] They lived at Wilbury House in Wiltshire.[1]

By his first wife, St Just was the father of Laura Claire Grenfell (born 1950), and by Maria Britneva he had two further daughters, Katherine Grenfell (1957),[1] known as Pulcheria,[6] and Natasha Jeannine Mary Grenfell (1959). His daughter Katherine married Oliver Gilmour.[1]