Mr Al Fayed will get the most public airing for his theories yet in what is expected to be a high point in the inquest that has run for more than four months and cost more than 2 million pounds (S$5.6 million).

Mr Al Fayed drew his own conclusions within half an hour of his son Dodi's death, according to Mr Frank Klein, president of the Ritz Hotel in Paris.

'This is not an accident, this is a plot or an assassination,' Mr Fayed said in a telephone conversation, Mr Klein has testified.

'I am in no doubt whatsoever that my son and Princess Diana were murdered by the British security services on the orders of HRH Prince Philip, Duke of Edinburgh,' Mr Al Fayed said in a witness statement three years ago.

He has also declared: 'I'm the only person who knows exactly what happened.' On Thursday, however, Mr Al Fayed's security chief, Mr John Macnamara, said the billionaire had no evidence implicating Prince Philip.

Mr Macnamara also said he had no evidence for previous assertions that Princess Diana had telephoned friends with news of an impending engagement, that the British ambassador in Paris ordered her body embalmed to cover up her pregnancy, or that the French medical team that treated the dying princess were involved in a murder plot - all allegations made by his boss.

That's unlikely to dent the confidence of the combative Mr Al Fayed, who worked his way up from a humble birth in Alexandria, Egypt, in 1929 to become one of the richest men in Britain.

Stubbornly rejecting the findings of French and British police that his son died in a simple road accident, he has used his wealth to pursue court cases in Britain, France and the United States seeking evidence of collusion among security agencies.

Despite owning the Harrods department store in west London, a castle in Scotland and the Fulham FC soccer team, Mr Al Fayed has been a frustrated outsider in his adopted country.

He has been thwarted in his applications for British citizenship, and caused a political uproar in 1994 when he disclosed that he had paid two members of the House of Commons to put questions to ministers.

Mr Al Fayed began building his fortune as a furniture dealer, and had profitable dealings with his brother-in-law, Mr Adnan Khashoggi, who later became a major arms trader.

Mr Al Fayed and his son Dodi, the product of a brief first marriage, moved to England in 1974.

Mr Al Fayed defeated another colourful entrepreneur, Mr Tiny Rowland, to gain control of Harrods in 1985. Five years later, a British government report concluded that Mr Al Fayed and his brother Ali had misrepresented their background and the sources of their wealth when they bought Harrods, but no sanctions were imposed.

Mr Al Fayed's lawyers have not yet outlined a comprehensive theory of the alleged murder plot, though they have asked pointed questions about Prince Philip, the letters he wrote to Princess Diana, now missing; and the now-legendary white Fiat that investigators say bumped against the couple's car just before the crash. -- AP