When Princess Diana died unexpectedly in a car crash in Paris in August 1997, it unleashed an extraordinary and unprecedented display of emotion in Britain: the mountains of flowers outside town halls across the country, the avalanche of letters, the seemingly endless queues to sign one of the forty books of condolence, and the visible distress and grief in multitudes of people.

Gallup conducted a poll at the time to ask Britons to indicate just how upset they were. Half of all respondents (the majority were women) said they were saddened, as if a personal friend had died. Although no definite causal link was established with the untimely death of the "People's Princess", the suicide rates in England and Wales - particularly among young women - were found to be 17 per cent higher in the first month after her funeral, while the rates of self-harm rose by 44 per cent in the first week.