Back in the old empire days, we had a phrase for those who forgot the basic elements of Britishness, and got too caught up in the strange mores of whatever imperial dominion they happened to be residing in : going native.
I used to think that Tony Blair was the only Briton who had ever managed to go native on one of the colonies without actually living there; but now I see that there are many others like him.
The increasing adoption of American mores and terminology in Britain is a sign of a country that has lost touch with its own soul. Blair's push for a "Supreme Court" and a "Freedom of Information Act" was a sign of someone who was so psyched out by America that it went well beyond the realm of the rational. America had invaded and occupied the deepest, subconscious layers of his psyche.
Now we see a similar phenomenon spreading across the whole of Britain. As this report in the Times indicates, many British schools have now adopted the grotesque American practice of hosting a "school prom." Those Britons with any sense of self-respect left must cringe at this absurd importation.