Trident??
So if we had a minor conventional skirmish with pro-Russia or Russian forces on the fringe of Europe that lead to a small but precise retaliation of conventional cruise missiles against 2 or 3 RAF bases you would suggest reaching for thermonuclear weapons?
The threat of a small-scale, limited but precise conventional attack by stand-off weapons is a credible threat because of the increased likelihood of the use of such a tactic. Indeed, it is one we have exercised ourselves a number of times in various conflicts post-1990.