Wrong attitude, I'm afraid.
The more technology progresses, the more likely smaller countries are to be able to build their own nukes.
As such, the main deterrent is having our own. It won't deter utter lunatics who don't care about their own lives or the lives of their citizens, but it stopped the Russians and Americans from launching during the Cold War and it's working at the moment pretty well too.
What would we do if the CND got rid of all our nukes, then someone threw one at us? Just sit and cry?
We're at that delicate stage in Civilisation in between getting the Bomb and developing the missile shield that protects you from it.