LONDON, March 2: The father of Princess Diana's lover won a significant legal battle on Friday when the High Court decided that the inquest into their deaths in a Paris car crash 10 years ago should be heard by a jury.

Mohamed al Fayed, who is convinced his son and Diana were murdered, had sought to overturn a ruling by Britain's former top woman judge Elizabeth Butler-Sloss to handle the official inquiries on her own.

Three senior judges ordered that the coroner hearing the inquest `shall do so sitting with a jury’.

Speaking to reporters outside the court, Mr Fayed said: “We want to be sure that the jury are an independent jury.”

He said he hoped Diana's ex-husband Prince Charles and ex-father-in-law, the Duke of Edinburgh, would be called as witnesses.

Appeal court judge Janet Smith, handing out the High Court ruling, said: “Mr Al Fayed has alleged that the Duke of Edinburgh and the Security Services conspired to kill the Princess and Dodi Al Fayed.

“The allegation must be inquired into,” she said.

Diana, 36, Fayed's son Dodi, 42, and their chauffeur Henri Paul were killed when their Mercedes limousine smashed at high speed into a pillar in a Paris road tunnel as they sped away from the Ritz Hotel, pursued by paparazzi on motorbikes.

A three-year British police investigation ruled at the end of last year that the crash was an accident and not part of an elaborate murder plot as Fayed claims.

The British inquiry backed a French probe which concluded that the driver was to blame because he was drunk, under the influence of anti-depressants and driving too fast.

Diana's children, Princes William and Harry, had expressed the hope that the long-awaited inquest would be `open, fair and transparent’ and completed as fast as possible.

Hello Magazine's royal correspondent Judy Wade said: “This just prolongs the agony for William and Harry, but Mohamed al Fayed is a grieving father who wants a small triumph like this which would help give him some closure.”

Evening Standard royal reporter Robert Jobson said: “The princes wanted it to be cleared up as quickly as possible which it clearly won't be. But everybody wants it to be a transparent and fair hearing.”

Under British law an inquest is needed to formally determine the cause of death when someone dies unnaturally.—Reuters