Diana's post-mortem samples were switched with those from another woman, an explosive new book claims. Adding weight to "cover-up" theories, it says samples were swapped prior to toxicological testing. According to documents uncovered for the book, published this week, the toxicologist at London's Charing Cross Hospital received the samples of another female and tested them in the belief that they were from Princess Diana.

In his latest volume in a series about the Diana inquest, author John Morgan believes he has discovered the truth of what occurred in the 24 hours following the deaths of the Princess and Dodi Al Fayed in a Paris car crash on August 31, 1997. "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 last night, pointing out that the documents were, along with others, withheld from the inquest jury.

Mr 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." 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 was no embalming fluid in the toxicology tested samples."

He went on: "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."

Mr 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. "I am asking why?" said the Australian-based writer who lives in Brisbane and insisted that documentation shows interference from senior aides on behalf of the Queen.

"Having removed Princess Diana as a member of the Royal Family in 1996, suddenly, Diana became royal again. Only the Queen could have ordered this. "The Queen took control of events from Balmoral, very early following Diana's death," Mr Morgan said, adding that he believed the UK coroner should not have taken possession of Diana's body after it arrived back in England.

"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." Another stark example of a switch Mr Morgan claims to have discovered was that there was no vitreous humour (eyeball gel) sample taken during the UK post-mortem, yet a sample was tested by the London toxicologist.

Also, sample labels received by the toxicologist, Susan Paterson, for both blood and liver tests, read differently to the descriptions in the post-mortem documentation. Mr Morgan has spent more than five years investigating the evidence relating to the 1997 Paris crash in the city's Alma Tunnel.

His series of books is based on the testimony heard during the inquest and evidence in official documents from within the British police investigation that were withheld from the inquest jury. Leading QC Michael Mansfield, who served throughout the six months of the London inquest, stated last year: "I have no doubt that the volumes written by him will come to be regarded as the Magnum Opus on the death crash.

Dodi's father, Mohamed Al Fayed, has praised Mr Morgan's work, calling it "heroic" and "impressive works of forensic enquiry and immensely helpful to the cause of truth." Mr Al Fayed said: "I believe that John Morgan has done more to expose the facts of this case than the police in France and Britain."

Diana Inquest: Part 4: The British Cover-Up by John Morgan, published by Lightning Source UK Ltd, available on Amazon UK, (www.amazon.co.uk) priced £17.89.