Mitchell is survived by his wife, the Actress Celia Hewitt, whose bookshop, Ripping Yarns, was in Highgate, and their two daughters Sasha and Beattie. He also has two sons and a daughter from his previous marriage to Maureen Bush: Briony, Alistair and Danny. There are nine grandchildren: Robin, Arthur, Charlotte, Natasha, Zoe, Caitlin, Annie, Lola and Ollie. Mitchell and his wife had adopted Boty Goodwin (1966-1995), daughter of the Artist Pauline Boty, following the death of her father, literary agent Clive Goodwin, in 1978. Following Boty Goodwin's death from a heroin overdose, Mitchell wrote the poem 'Especially when it snows' in her memory.