'Diana was pregnant when she died - but Dodi was not the father' claims French journalist

French investigative journalist Chris Laffaille says he uncovered evidence of the pregnancy from official archives of the Paris hospital where the princess was taken after the crash on the night of August 31, 1997.

If genuine, says Laffaille, it would mean Diana's unborn child would not have been fathered by Dodi Fayed because she had not met him nine weeks before her death.

Scroll down for more

Instead, he said, the baby may have been conceived while she was seeing London doctor Hasnat Khan.

Laffaille makes the claim despite a categoric statement by John Burton, former royal coroner present at the post-mortem examination on Diana, who said: "She wasn't pregnant. I have seen into her womb."

Laffaille, a former reporter with the magazine Paris Match, says he has conducted a detailed re-examination of all the evidence surrounding the crash.

The resulting book, Diana: The Inquiry They Never Published, is being released on August 27.

It is being described as one of many attempts to cash in ten years after Diana's death but it also revives conspiracy theories that have plagued the investigation into how she died.

Scroll down for more

Laffaille agrees with the verdict of the official French inquiry in the crash, that Diana and Dodi were the victims of a high speed drink-driving accident.

But he also says there are still "many unanswered questions" surrounding the death, especially the issue of whether Diana was pregnant.

He said: "It is a near certainty that Diana was nine to ten weeks pregnant at the time she died, according to papers from the Paris Public Hospitals archives.

"The letter dated August 31, 1997, was sent to the then minister of the interior Jean-Pierre Chevenement, and copies sent to health minister Bernard Kouchner, foreign affairs minister Hubert Vedrine and the Paris police chief Martine Monteil."

Scroll down for more

Laffaille added: "This document has never been claimed or proved to be a fake."

However, a spokesman for the Paris Public Hospitals last night dismissed the letter as a forgery, which had first been circulated shortly after Diana's death.

"Examination of this document has established with absolute certainty that it is a fake," he said.

"It is ridiculous. Many of the medics who treated Diana remain at the hospital, and all deny the claims contained in this forged letter."