Frances Mary Allen was born in Disley, Cheshire to Frances Hannah ( Smalley) and John Nelson Allen. Her father was the director of a tobacco company but he died when she was a baby and he was in his forties. Clutton-Brock and her mother moved to Eastbourne on the south coast after her father's death. Clutton-Brock went to school in Eastbourne but left quickly when she was fifteen and disappeared to the continent where she travelled around Europe. When Clutton-Brock returned she learned how to teach handicrafts and found work in the borstal service. She married Guy Clutton-Brock who was a probation officer working with borstals on 14 April 1934.
