According to the book, `Diana Inquest: Part 4: The British Cover-Up`, the late Princess of Wales` inquest samples were swapped prior to toxicological testing at Charing Cross Hospital in London.
In fact, the toxicologist received the samples of another female and tested them in the belief that they were from Princess Diana, the book claims.
Author John Morgan says he believes he has discovered the truth of what occurred in the 24 hours following deaths of Princess Diana and her boyfriend Dodi Al-Fayed in a Paris car crash on August 31, 1997, the `Daily Express` reported.
"There is a lot of evidence which points to the toxicology testing being carried out on samples that did not come from the body of Princess Diana," he said, claiming the documents were, along with others, withheld from inquest jury.
Morgan said he had uncovered a litany of conflicting evidence, inconsistencies, mis-labelling of body samples, cover-ups, evidence and witnesses who were never called to give evidence at the inquest.
He is now calling for independent DNA tests to be carried out on the body samples. "The samples at Charing Cross Hospital have never been subjected to DNA testing. With so much conflicting evidence, how can we be sure?" he said.
"The evidence I have studied indicates that there are two lots of samples. One belongs to Diana, which is held by the Metropolitan Police`s Operation Paget, and the other lot are samples from another body and held by Charing Cross Hospital. Diana`s UK post-mortem samples were switched ahead of the toxicology testing," Morgan said.
He added: "The jury were not given the post mortem and toxicology reports on Diana. If they had, they should have been able to work out that the toxicology testing was conducted on samples that weren`t Diana`s.
"For example, Diana`s body was embalmed in France, but there`s no embalming fluid in the toxicology tested samples.
Diana had consumed alcohol that night in Dodi’s apartment and later at the Ritz Hotel.
"It is recorded by the Hammersmith and Fulham mortuary manager that her stomach smelled strongly of alcohol, but there was no alcohol in the samples tested in London."
Morgan said that within 24 hours of her death, Diana`s body had been subjected to embalming in France and the UK, along with two post-mortems. "By law, jurisdiction over the body should have gone to the coroner in Northamptonshire, which covers Diana`s family home, Althorp, where it was known Diana’s body would be buried," he said.