Finally having 4G in the UK is awesome, even if it is horrendously expensive. But what about when you travel with your brand new 4G phone? Right now you can't get 4G abroad, even though lots of other countries have LTE networks -- you'll have to wait till 2013 to find out how much it's going to gouge your wallet.
That doesn't mean you can't roam at all while in a far-flung country though, just that you'll be stuck in the slow lane with bog-standard 3G. It's unknown at this stage whether roaming on 4G will be more costly than 3G, and whether you can select one or the other on your plan. Of course, you could just turn the 4G radio off while skipping the country, which'll also save you battery, but where's the data-burning fun in that? [Cnet]