You might have thought that Royal siblings would have learned their lesson about the perils of attending fancy dress parties by now.

Pippa’s weekend away in Paris probably seemed like a good idea at the time; a lavish party on foreign soil, away from the glare of the British paparazzi, thrown by her old friend Vicomte Arthur de Soultrait, to celebrate his 30th birthday and the seventh anniversary of his swanky fashion brand, Vicomte A.

If Pippa had any reservations about attending a party which was largely a promotional event for a business, they were brushed aside. And, as the palace keeps insisting that she is a ‘private individual’, and is declining to provide her with security despite the fact that she (or more precisely, her bottom) has done more to reinvigorate the British Royal brand than any number of out-of-touch HRHs, and she has become a focus for random stalkers who have succeeded in kissing her in public places, she doubtless thought she might as well act like a private individual, and go where she bloody well pleased.

And what she pleased was to be guest of honour at Arthur de Soultrait’s Marie Antoinette and Louis XIV-themed party.

Let them eat cake, and all that.

Pippa might well have got away with nothing more than a nasty hangover and a few pictures of her entering and exiting the party, plus a few mean comments about her boring fancy dress outfit, had it not been for the fact that, while she was being driven back to the Gare du Nord to catch the Eurostar home, one of Pippa Middleton’s pals who was driving the car, produced a toy gun and aimed it, in an ill-timed jest given the recent spate of terror shootings in France, at a photographer.

The snapper sold the pictures to the British tabloid the Sun which then hyped the story to the max by speculating that the gun may have been real (despite the fact that another of the photographers pursuing Pippa said that he saw the toy gun and chatted to the occupants of the vehicle after the car parked up).

The British public are pretty experienced when it comes to sniffing out a tabloid hype-fest, and when it was revealed by a staff member at Vicomte A exclusively to the Royalist that the gun was indeed not real and the whole episode was ‘a stupid joke’, it might have been the end of the matter.

Unfortunately for Pippa, that is not the case. The story has now entered a second, potentially far more damaging phase, as hundreds of photos posted by the brand on facebook to promote the event have now started appearing in the British press.

The photos give the lie to the story, relentlessly peddled thus far in the media, that the Middleton children are just ordinary middle class girls.

The stack of photos will not make for very happy viewing at the palace today. First off there is the general impression of privileged debauchery, with a powerful overall air of entitled arrogance, not helped by the fact that everyone is dressed up in cullottes, ball gowns and white wigs.

Then there are the dwarves. Having novelty dwarves at a wild party is an old custom among some shock-seeking impressarios, but it doesn’t get any more tasteful as the years pass by. Let’s put it this way: going to a party where small people have been hired to walk around as a freak show, for people to laugh at, is unlikely to feature as a top tip in Pippa’s forthcoming party book.

The worst picture, however, from the Firm’s point of view, is the one in which Pippa grins broadly as she stands among a group of women surrounding Arthur, who has a studded bondage dog collar around his neck, which another of the girls is pulling.

De Soultrait certainly milked Pippa’s royal connection for all it was worth. A video of the event posted on French gossip website Gala culminates with a stripper clambering out of a cake to God Save the Queen. The party itself was entitled, ‘The King is Dead, Long Live the Viscount.’

There has always been a suspicion among the British people that the Middleton children were actually members of the idle rich, and the spotlight that Gungate has shone on Pippa’s party companions has now confirmed that hunch.

The plastic toy gun itself will rightly be forgotten before long, especially if, as ABC was reporting last night, the French police don’t press charges.

But the images of Pippa, the sister of the future Queen, grinning away alongside her idiotic over-privileged friends as they cavort in bondage gear alongside miniature men hired to provide freak show entertainment, might prove a little harder to erase from the national consciousness.

As the one year anniversary of the moment Pippa sprung to fame as her sister’s bridesmaid approaches, the question of just what she intends to do with her sudden and unasked-for celebrity is more urgently in need of an answer than ever before.