Diana loved pranks and practical jokes, and one of the most uproarious involved an item purchased on a wild staff night out in Paris, during her official visit to France in November 1992.
We all referred to it as 'Le Gaget', or the gadget - in fact, it was a sex toy.
I had persuaded Lady Sarah McCorquodale, her sister and acting lady-in-waiting during the trip, to secrete it in Diana's handbag the next morning.
The Princess discovered it while going through her bag, between meetings with the French president Jacques Chirac and Paul McCartney.
Far from being offended, she thought it very funny, and from that moment Le Gaget became her secret mascot on all royal visits abroard.
She attached almost superstitious importance to it and, when we arrived in Nepal the following March, she turned to me and said: 'I hope we've got Le Gaget, Ken. You know everything will go wrong without it.'
Much to her consternation, I had to admit it had been left in a drawer at Kensington Palace. A telephone call was made and a secretary instructed to dispatch the vibrator by diplomatic bag to the British Embassy in Nepal.
It arrived in a sealed packet, delivered on a silver tray by a gurkha aide to the King of Nepal, during a press reception at the ambassador's official residence.
The Princess was preparing to meet the media in the gardens when the package was handed to Diana's equerry, Captain Ed Musto of the Royal Marines - who made the ill-advised decision to open the packet and remove the offending item, in front of all the guests (but, mercifully, not in view of the world's Press).
There was a stunned silence.
Then the Princess said: 'Oh, that must be for me,' and started to laugh.
Captain Musto graciously slipped Le Gaget into his pocket, and the embassy dignitaries were far too diplomatic to make any comment. There were a few bemused glances, though.
- Ken Wharfe was a former Royal Bodyguard to HRH Diana-Princess of Wales