Suicide rates shot up as a direct result of the death of Princess Diana, according to an Oxford University professor.

A study led by Prof Keith Hawton, an expert on suicide, revealed the increase was particularly marked among women in the princess's own age group - between 22 and 45 - in the weeks after her death.

Overall, the suicide rate in England and Wales in the four weeks after Diana's funeral rose by 17.4 per cent, from an average of 90 per week to 107.

Prof Hawton said: "It is known that major events - particularly the death of celebrities - can influence the rates of suicidal behaviour.

"The death of the Princess of Wales was arguably the event that had the widest effect on public emotions in recent years and received the greatest media coverage."

Psychiatrists involved in the study believed the princess's death, at the age of 31 in a Paris car in 1997, led to an unprecedented outpouring of grief that drove many over the edge.

In Oxford alone, the study reveals the number of hospital admissions for overdoses and other cases of self-harm, rose sharply immediately after Diana's death.

Researchers said that medical case notes suggested those who took their own lives found public grief amplified their personal troubles.