and this is assuming that the nuclear blast radius isnt big enough to cover entire uk, of course that seems very unlikely because it is a big place and look at scotland for example, if a nuclear blast went off in london the distance from there to scotland is very far so far that the blast radius would have to extend into the ocean and possibly hit other countries like france. but that is neither here nor there, so as to who fired the nuclear missile at london would probably be russia although im not sure if i realized that in my dream and just looked out the window and see it coming from miles and miles away in london and shouted something like "oh shit! that's a nuclear missile!" which of course, would be the correct response because extreme fear should be your first thought when seeing a giant nuclear rocket slanted at an 145 degree and is slowly descending in the distance. unless of course, you're suicidal.
United Kingdom