A Francophile, Mortimer broke down in tears when he heard on 21 June 1940 that France had signed an armistice with Germany, saying it was as if half of England had just fallen into the sea.
[1] He later became literary editor of the New Statesman, worked at the BBC and in liaison with the Free French in World War II, and subsequently as a book reviewer for The Sunday Times.
He was a friend of the poet and novelist Vita Sackville-West, and was involved in a long-term relationship with her husband, the author and British diplomat Harold Nicolson.
Mortimer joined the three owners of Long Crichel House in Dorset, friends Edward Sackville West, Desmond Shawe-Taylor and Eardley Knollys, as one of the residents, after World War II.
[2] There they held salons, entertaining some of the great literary and artistic figures of the day, including E.M. Forster, Nancy Mitford, Benjamin Britten, Laurie Lee, Ben Nicolson and Graham Greene.