Remember that when all the Armageddon type BS was being spouted about nuclear war most nukes were highly inaccurate city buster of 20 to 50 megatons each and many were expected to be ground burst weapons, these beasts create huge amounts of fallout. Modern nukes on all sides send to be pin point accurate kiloton range AIR burst devices and provided you are no in line of sight of the device when it goes off you can probable survive. Remember nuke blasts like all explosions still only travel in straight lines so if the nuke went off over Leeds chances are Manchester would only suffer the EMP effects. And if the devices are air burst then their will be little or no dirty fallout to contend with.
Both sides soon realised with big city buster nukes that if for example the US vapourised Moscow with three big megaton devices that eventually much of what was Moscow would float down on New York ( and everywhere else) and poison it. So most modern militarys choose accuracy over power which is good for anyone in the target country.