Free Thinking: Lady Antonia Fraser

From Mary, Queen of Scots, who her mother was going to write about until she intervened - to her most recent biography of Caroline Lamb, out in mid-May, Antonia Fraser has had a career publishing prize winning books exploring historical figures. In this conversation, recorded at her London home with historian Rana Mitter, she reflects on what she calls "optical research", the crime fiction she has written, and meeting figures from history