What makes a great love story? Imagine looks at the great books, films and pop songs that have tackled the thorny issue of love, pain and desire. Lancelot and Guinevere, Wuthering Heights, Pride and Prejudice, Lady Chatterley's Lover, 24 hours from Tulsa, Casablanca, Brief Encounter and Lolita are all great love stories. But what makes them special?

'A great love story has to have a fly in the ointment', according to Pulitzer prize winner Jeffrey Eugenides. Other contributors include best selling authors Sarah Waters, Helen Fielding, Jane Austen's biographer Claire Tomalin, Burt Bacharach's lyricist Hal David, screen doctor Robert McKee, psychoanalyst Adam Phillips and literature professor John Sutherland.