Central to the conspiracy theories around Princess Diana’s death was an accusation that Princes Charles and Prince Philip had been involved in a plot to kill her in a staged car crash - fears voiced by Diana herself in a letter to butler Paul Burrell. In the fifth of our seven-part series, award-winning crime writer Stephen Wright talks exclusively to Lord Stevens, the former Metropolitan Police Commissioner who led Operation Paget, about the moment he had to ask Prince Charles whether he had a hand in murdering his wife... and about a mysterious sum of money found in chauffeur Henri Paul’s bank account.

Produced by Rosie Gillott