It would really depend. I don't think the Fallout canon has anything to do with the UK, though I imagine they would be the US's allies in the war. So maybe there would be a little nuclear action going on.
ghostracoon16 said:
No, because there is no vaults in England.
Also, this. There would be no vaults in the UK. I'm not saying that it would be impossible to make one simply because there are no vaults, since people managed to stay alive outside of vaults anyway, but no vaults means no Pip-Boys. The Pip-Boy is a device that, not in-game mind you, bridges the noticeable gap between game and character. It gives you a tangible device that gives you information, so that you aren't just looking at in-game menus. I feel like no Pip-Boys would take away the subtle charm that it provides, which would actually do more damage than it may seem. The developers may have to think of a clever work-around, without ruining the canon.