In the cold light of day it is probably not madness.
Back in the day the mission was to defend the nuclear deterrent. After 1982 it continued more out of habit. 26 years after the cold war things have changed out of all recognition. Russian conventional forces are not capable of a massive air assault on UK and at the same time the number of military target has reducecd greatly.
OTOH the political threat of nuclear attack is very real and our defence wholly on counter attack.