True, most of us would have been fried although airburst bombs may have been the preferred Soviet blast of choice, does the job without less fallout.That supposes that the soviets actually thought they could win a nuclear war and occupy a burnt and contaminated western eurpoe as a prize.
A chain of hardened silos though need accurate groundburst warheads, the studies into silo-ing Blue Streak in the 1950's concluded that the most suitable rock strata was in southern england, a political non starter,particularly once Blue Steel, Skybolt and then Polaris lessened the need. I recall the controversy of the GLCM's at Greenham Common, I believe Pershing was equally controversial in Gemany? Understandibly if your homeland was the conventional and the nuclear battlefield. Thankfully it never happened.
Plus the 4 minute flight time from western russia to the UK must make things less flexible, they could be hit before they had the chance to fly, and that puts immense pressure on any risk of false alarm, I doubt any politician could consider the matter and make a rational decision in 4 minutes so the process would probably have to be automated or at least have devolved responsibility to a senior military commander with his/her finger permanently next to the button?
As I understand it later Minuteman models took less than 30 minutes to reprogram and retarget eg, there is no point firing at an empty silo if the soviets launched a first strike,retarget and hit an industrial/population target. If your silos are in midwest USA, you get 30 minutes warning. Of course the soviets tried cold launch techniques to make their silos more "attractive" because they could in theory be reloaded. With silos in the vastness of empty siberia, perhaps Russia could have actually played the numbers game and won?
In the recent UK "should we replace Trident?" debate, ground launch and silos was a non starter. Protestors cant get near a submerged submarine, there is always a risk that they manage to chain themselves to a silo, and we arent allowed to shoot protestors.....