Betsy and Napoleon: After Waterloo

After his defeat at Waterloo, Napoleon was exiled to the island of St Helena. There he struck up an unlikely and intense friendship with Betsy Balcombe -- the daughter of a British family -- who hosted him until his permanent residence was ready. Julia Blackburn, author of Betsy and Napoleon, this week's drama on Woman's Hour, talks to Jenni Murray about the former emperor and his outspoken and playful companion.