Mary was born in a small and uninteresting country town but the family moved to London when she was three. Just before she was seven she had her appendix removed by Enid Blyton's husband!! At primary school she wrote plays which her friends performed.
In 1964 Mary went to Cambridge University to read English Literature and in 1970 she started writing her first book, White Magic. Since then she has written about 80 books for children.
Stravaganza: City of Masks was written in Mary's study in her old converted barn in Oxfordshire, which has a silver mask on the noticeboard and a vase of peacock feathers in the fireplace. The sequel - City of Stars was inspired by a terracotta tile of a flying horse, bought in Sienna, and a shield featuring the ram of the Valdimontone district of that city, where the Palio horse race is held twice each summer.
In her spare time, Mary attends Italian literature classes each week, produces four issues of the children's book review magazine Armadillo every year, reads voraciously and plays with her Burmese cat, Kichri, who is her most devoted companion.
Mary's married and has three daughters.