It's the same in so many things.
Manufacturers will charge the same price in dollars as pounds, and so make ahuge amount of extra profit.
In this case there is no excuse that the camera needs to be different for a different markwt, it's simply greed.
Bear in mindm however, that if you try to import the camera you'll end up getting slapped with import duty and VAT PLUS they have the nerve to charge you VAT on the carriage costs and then impose a 'handling fee' for the pleasure of ripping you off.
Add to that the fact that Canon UK will probably make a huge fuss if you need to make a warranty claim despite the worldwide warranty ascribed at purchase, and you'll probably be better of buying in the UK.
On the other hand, if you have an American friend who can take delivery and repost it to you, he could declare the package to be 'personal possessions' and you can avoid all the hassle. Of course, you do run the risk of Customs opening the package and asking for payment anyway.