It's a tough call for the policemen in charge of royal protection on the occasion of the family's big shindig. On the one hand, if the amiable hippies in charge of Glastonbury can get their heads around a ticket-only entry system, law enforcement officers of far more advanced jobsworth tendencies should have been able to prevent the gatecrash coup of a comedian dressed as a well-known terrorist. And yet, on the other hand, imagine the conversation - "I have a man here, sarge, dressed as Osama bin Laden." "That's no good. Where's the fun in that?" "Well, given that the right-thinking individual doesn't find terrorism in any way amusing, I imagine the joke is that Johnny Foreigner is a funny fellow." "Oh, I see, well you'd better let him in, then. That's the theme of the   party." "Is that what Out of Africa means?" "Yup. Pretty much." In a craven attempt to get some goods on William's sex life, certain newspapers have decided that his fancy dress idea derives from the hots he harbours for Jessica Craig. According to the Sunday Times, she is a 21-year-old member of "Kenya's white elite", though whether you can ascend into this white elite just by being white, or whether you have to be loaded as well, remains unclear (lest there be any doubt, however, she is also loaded).  The historian Andrew Roberts considers the theme as part of the wider family's relationship with the African continent. "There is an inverse proportion between the amount of time the Windsors spend in Africa and the amount of power they have   there. After decolonisation, they went more and more." I suppose the message there is that this is a very nice family which just gets along much better with people it is not actively oppressing. The party theme is therefore a loud hello to celebrate the end of a pernicious empire. But really, to interpret this as either a romantic or a political gesture is to back away from the glaring truth that this is party theming as devised by a complete arse.  First, although no reports have been exhaustive on the subject of Will's guest list, all the people who have been mentioned seem to have names that start with Second Earl of ... I wouldn't want to embarrass the palace by checking, but I am prepared to bet that the only black people at the party   were members of the band. While nobody can force a young Botswana-travelled royal to have African acquaintances who are not members of its "white elite", the act of making his whitey friends dress up in feathers rather tastelessly underlines the fact. After all, you probably wouldn't have an American-themed party if you had Americans you wanted to invite. They would turn up in their regular clothes, for one thing, and besides, might experience feelings of miffedness.  Imagine if someone in Africa had an English-themed party. There would be a lot of top hats and fans; some Jane Austen wear for people prepared to make the effort; a few wags might arrive with fake 12-bores and try to subjugate the rest of the party (with hilarious results); a costume of an   animal commonly associated with our island (in all probability, a pig) might make an appearance. The japes would be many and varied, but from our point of view, pretty insulting, having fallen back on the keystone cliches of Englishness - that we are starchy, uptight, brutal and we like bacon sandwiches.  Any attempt to represent a nation with its dress is bound to be reductive and therefore dehumanising. It stresses the otherness of foreigners, and rejects the global truth that most people, the world over,   dress more or less the same, apart from the ones who can't afford a telly.  Furthermore, if you look at the individual costumes chosen, you get an even stronger tang of - well, not wishing to bandy the "racism" word around too freely, let's call it "look at the funny natives-ism". There was a lot of leopard print and snakeskin which (on the basis of only one visit to Africa, granted), I'd say was a closer approximation of a Streatham singles night than an African style statement.  Many of the older gentlemen dressed up in safari suits, which is like going to a Spanish-themed party with a beer, a burger and some vivid red sunburn (sure, there are English people in every country, and they tend to look funny, but you wouldn't say they defined that country's aesthetic). Fergie   wore a long silver wig and whatever the message behind that, I'm sure, even if I knew, I would find it very offensive.  And finally, there is something unsettling about the ongoing (I believe unrequited) love that the posh have for Africa. It does not focus on the realities of its countries in their modern form, but rather is shot through with a plangent nostalgia. And honestly, the subtext of any nostalgia about this continent has to be that it was better when we still owned it.  All told, these are some very murky messages for a 21-year-old to be encouraging. It must be hard to get things right, living perpetually in the public eye. But he could afford to be a lot more dudelike, without getting any less regal.