LONDON (Reuters) - The procedures used by French medical experts to collect samples from the body of Princess Diana's chauffeur suffered "inconsistencies", the inquest into her death was told on Monday by a leading British toxicologist.

French and British police investigations have both concluded that Diana and her lover Dodi al-Fayed died in a high-speed Paris car crash because chauffeur Henri Paul was drunk.

But Dodi's father, luxury storeowner Mohamed al-Fayed, alleges that her son and Diana were killed by British security services on the orders of Prince Philip.

He has also questioned the results of the tests taken on Henri Paul's body after his death.

Professor Robert Forrest, who reviewed all the medical reports into Paul's death, ran through them again in meticulous detail for lawyers at the inquest.

The court was told that important blood samples from Paul were originally thought to have come from the heart but in fact came from his chest cavity, a much less reliable measure.

Forrest said Dr Gilbert Pepin, responsible for the French toxicology tests, believed they were heart samples.

"I was there when Dr Pepin was told it was not cardiac blood, it was chest cavity blood. I still have a vivid recollection of the way that his face changed when he was told. He looked surprised," Forrest told the court.

There was also confusion over just how many samples of blood were taken and when exactly they were taken.

"There are unresolved incompatibilities -- inconsistencies I should say rather than incompatibilities," Forrest said.

He told the court: "The interpretation of samples is only as good as the samples themselves," he told the court.

"It doesn't matter how sophisticated the analysis is, if you don't have good material to work with, you have to qualify the interpretation of the data your laboratory generates," he said.

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