Greetings, Shun- welcome to my blog!

The way I understand it, the iPhones are “locked” so that they only work with a single carrier. American iPhones only work with AT&T, and so I would expect the British ones only work with O2 (the company “blessed” by Apple to provide iPhone service there).

So, at least without hacking, a British iPhone wouldn’t work elsewhere. I’m sure the phones could be unlocked using various unapproved hacks, but then you’d have a phone that could at any moment be disabled by Apple with the next OS update.

This carrier lock-in is one of several reasons that I’m not really that impressed with the iPhone. The one thing it has going for it is an elegant UI, and I personally find its downsides significantly outweigh that singular benefit.