foot was born on 23 february 1961 and is the daughter of the military historian m. r. d. foot and his second wife elizabeth. she was educated until 1979 at withington girls' school in manchester. she then went up to newnham college, cambridge, to study at the department of anglo-saxon, norse, and celtic, where she was taught by, amongst others, rosamond mckitterick and simon keynes. she gained her doctorate in 1990. her doctoral thesis, written under the supervision of rosamond mckitterick, was titled "anglo-saxon ministers, ad 597 – ca. 900".