Mohamed Al Fayed will appeal a judge's decision preventing a full public inquiry taking place in Scotland into the death of his son.
Mohamed Al Fayed: "Dismayed" at ruling
Lord Drummond-Young has ruled that the
Scottish Executive acted lawfully in refusing his request for a probe into the death of Dodi and Diana in 1997.
The decision follows a court hearing last year in which the Harrods owner sought a judicial review.
Mr Al Fayed owns a home in Scotland, allowing him to make the application.
At the Court of Session in Edinburgh, Richard Keen QC, Mr Al Fayed's lawyer, said there were "numerous matters which cast material doubt" on the official explanation of the 1997 crash in Paris.
A French inquiry concluded driver Henri Paul, who also died, was drunk and on anti-depressants and blamed him largely for the fatal crash.
But in court, Mr Al Fayed's senior counsel said his client had reached the "reasonable belief that the life of his son Dodi may have been taken by force".
Mr Keen said UK and US security services monitored Dodi and Diana leading up to their deaths and claimed Mr Paul may have been an MI6 informant.
The princess and Dodi Al Fayed died in 1997
Scotland's senior law officer, Lord Advocate Colin Boyd QC had previously refused to hold an inquiry, prompting Mr Fayed's call for a judicial review.
Mr Al Fayed, who owns the Balnagown estate in Easter Ross, said: "I am deeply disappointed and dismayed Lord Drummond-Young has ruled in favour of the Scottish Lord Advocate's decision.
"I will be appealing against this ruling. I made my application for a public inquiry in Scotland because my first home in Britain is in the Highlands.
"But the Scottish Lord Advocate, Colin Boyd, QC, has proved himself to be a poodle of Westminster and the Scottish Executive have allowed themselves to
become mere puppets of the mandarins of Whitehall.
"Nothing will deter me from pursuing answers to the many questions about the tragedy that I and millions around the world still seek."
He said he was "gratified" English coroner Michael Burgess had opened an inquest but claimed it had only a limited scope and would not reveal the facts of the Paris tragedy.
He added: "The present government has been quick to launch public inquiries recently to investigate matters of public interest which impact on its own credibility.
"When it comes to the death of Princess Diana, the mother of the future king, the issues are of even greater public interest and importance.
"We expect and demand the truth and only a full inquiry under the most rigorous public scrutiny will suffice."
Last December Mr Al Fayed claimed the Princess and Dodi were "murdered", as he launched his latest legal bid to have an official inquiry into their deaths.
The Egyptian-born tycoon argued a French inquiry failed to adequately investigate the crash and that he was entitled to one under Article 2 of the European Convention on Human Rights (ECHR).