The French public prosecutor has ordered an investigation into accusations by the former bodyguard that the Ritz and the exclusive Etoile limousine hire firm were guilty of "putting others in danger".

Diana. Princess of Wales, died in hospital

The hotel had ordered the Mercedes in which the princess was travelling with her boyfriend Dodi al-Fayed when it crashed.

Mr Rees-Jones was in the car as Dodi's regular bodyguard.

Ritz security man Henri Paul, who was three times over the drink-drive limit, was driving. He had taken tranquillisers and was not licensed - as required under French law - to act as chauffeur in such a vehicle.

The public prosecutor agreed on Thursday to pursue a lawsuit filed by Mr Rees-Jones in Paris last month.

Only survivor

His solicitor David Crawford said in a statement that the crash judge Herve Stephan has been requested by the prosecutor "to conduct an inquiry into the alleged offence of putting others in danger".

Mr Crawford said: "The basis of the allegation is that the Mercedes which was involved in the crash was hired out without a driver, contrary to the French penal code which regulates such contracts.

"The purpose of the complaint being made is to enable Trevor Rees-Jones to obtain compensation for the injuries and other loss which he has suffered."

Mr Rees-Jones was the only occupant of the car wearing a seat-belt when it swerved out of control in a Paris underpass and smashed into a concrete pillar.

Trevor Rees-Jones' complaints have resulted in the criminal investigation

Dodi al-Fayed and Henri Paul were killed outright. The princess died later in hospital.

Mr Rees-Jones, from Oswestry, Shropshire, suffered serious facial and back injuries and spent weeks in hospital.

He has since left his job working for Mohamed al-Fayed.

A technical report published last week on the Mercedes revealed that it was not faulty at the time of the fatal journey.

Experts put its crash speed at about 62mph, twice the legal speed limit in the underpass but far lower than originally estimated.

Potential witnesses

Mr Crawford raised the question of compensation with Mr al-Fayed's French lawyer in September 1997, just weeks after the accident.

"He made it quite clear that his client had no intention of paying any," the solicitor said on Thursday night.

Driver Henri Paul was over the drink-drive limit

The lawsuit could result in charges against the Ritz and the limousine firm.

So far Judge Stephan has interviewed their staff only as potential witnesses.

The alleged offence carries a maximum penalty of a £10,000 fine and a year in prison.

Such a prosecution would pave the way for a damages claim by Mr Rees-Jones, who has been questioned as a witness by Judge Stephan several times but who still remembers little detail of the fateful night.