She has been hailed as a brilliant observer of manners, the natural successor to Jane Austen and the mistress of the aga saga. As a serialisation of her latest book begins, Jenni Murray meets Joanna Trollope. Serial: The Best of Friends by Joanna Trollope. Penelope Wilton reads the first of 13 parts. Abridged by Pat McLoughlin. "When life is rocky where do you turn but your oldest friends....?"