She was born in Cheshire, the daughter of Rev James Mulleneux Prescott and his wife Margaret (née Warburton). She was educated at Wallasey High School. She read Modern History at Lady Margaret Hall, University of Oxford, where she received her first M.A.. Subsequently she was awarded a second M.A. at Manchester University, where she did research under the direction of Thomas Frederick Tout, professor of Medieval and Modern History. She was awarded an honorary D.Litt. by the University of Durham. In 1958 she was elected Jubilee Research Fellow at Royal Holloway College in the University of London, where she worked on Thomas Wolsey.

H F M Prescott is best known however for her historical novel The Man on a Donkey. Written in the form of a chronicle, the book tells the story of the Pilgrimage of Grace, a popular rising in protest at the Dissolution of the Monasteries by Henry VIII. Her biography of Mary I of England, Mary Tudor (originally titled Spanish Tudor), which won the James Tait Black Prize in 1941 remains one of the leading works on Mary I's troubled life and reign and is named by the Encyclopaedia Britannica as the best biography of the monarch.

H.F.M. Prescott wrote only one thriller, Dead and Not Buried, and this was adapted for CBS's Climax! television series under the screen title of Bury Me Later in 1954.

As the daughter of a clergyman, H.F.M. Prescott was a committed member of the Church of England and her wide-ranging interests included travel and a deep love of the English countryside. She was a woman of refined but simple tastes, and lived for many years quietly with her dogs in the Oxfordshire village of Charlbury. She died in 1972.

• Flamenca (1930). Published by Constable & Co (Attributed to Bernardet the Troubadour. Translated from the Thirteenth-Century Provençal by H F M Prescott)

H. F. M. Prescott