The death of Princess Diana “is far more complex than any of us thought”, said former Metropolitan Police Commissioner Lord Stevens yesterday. But that was as far as he went.

The investigation was ordered almost two years ago by the Royal Coroner after a French judge ruled the death an accident caused by a mix of bad decisions, and involving a driver who was drunk.

The father of the Princess’s boyfriend, who also died in the crash, Mohammed Fayed, has claimed that the crash was the result of a plot hatched by Prince Philip and carried out by British Intelligence. This, though, would also have implicated Tony Blair and other ministers, and seems a plot too far.

The “complexity” claim by Lord Stevens may just be an explanation for the delays in reaching a conclusion.