The Xbox 360 price cuts which Microsoft has recently bestowed upon the U.S. and Japan will not be worldwide. In particular, the UK will not benefit from either sets of cuts, even though Microsoft is dropping the price of all versions of the 360 within the U.S.
Microsoft said that pricing is determined per-region, and they have no need to drop the price in the U.K. right now. Clearly they think that breaking the $200 barrier was important here, but not so much overseas. The reasoning for Japan is obvious enough, as they have a hard time competing as-is.