plan. >> it was almost like you were in a sort of james bond movie kind of. >> it was much simpler, in a way, than people make. >> starting in the summer of 1991, he bikes to kensington palace like he has for years to visit diana, but this time he carries a small tape recorder and a long list of questions hidden in his bag. >> cycled in, had lunch, maybe a few questions before lunch and a few after, then off again. >> he delivered the tapes to andrew morton who weaves them into a revealing book, more revealing than anyone expected. >> she was very open indeed about everything. and to a level where i was almost worrying, cautioned about what was being said. >> from her struggles with bulimia, depression, to her husband's alleged infidelities and her multiple suicide attempts, one of them happening when she was just three months pregnant with prince william.