It is unlikely anyone (in the once-and-future USSR) ever seriously considered nuking the Ukraine because it's downwind from Russia's agricultural breadbasket by the prevailing winds and the wind-driven fallout would put Strontium 90 in their milk for decades.
And to nuke the formerly great Britain would be suicidal because of the US & UK's 1958 mutual defence (sic) treaty. Any one of the US's ballistic missile submarines can nuke 288 separate targets in the (once-and-future) USSR, and their range is so great that they can sit offshore from Newport News and still hit Moscow.
With the dilapidated state that Russia's nuclear arsenal likely is in, they're in no position to nuke anybody. This is nothing more than vodka-fueled sabre-rattling.
“Any one of the US’s ballistic missile submarines can nuke 288 separate targets in the (once-and-future) USSR, and their range is so great that they can sit offshore from Newport News and still hit Moscow.”
As Trump told rocket boy “Don’t ever threaten the United States again.My button is bigger than yours and mine works”.