Laura Cumming's new book opens with the disappearance of her mother, Betty, as a child in 1929. Discovered, unharmed, after five agonising days, the exact circumstances of the kidnap remained shrouded in mystery for fifty years. In today's episode, a note arrives from abroad and the news is illuminating and heart-breaking.

Abridged by Katrin Williams
Produced by Elizabeth Allard Show less