Mysteries still remained after Diana’s death - was the Princess pregnant? Why did it take so long for emergency services to get her to hospital... and could she have been saved? In the fourth 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, the ground-breaking three-year inquiry into Diana’s death. Lord Stevens reveals how he began to put the conspiracy theories to rest - while leading forensic pathologist Dr Dick Shepherd explains the real reason why there were ‘gaps’ in the notes from the autopsy on chauffeur Henri Paul.

Produced by Rosie Gillott