And if that happens then I damn well hope we retaliate.
Of course, we would retaliate that's the whole point of the Vanguard subs and Trident D5 SLBMs. The problem is if the Russians destroy our one patrolling Trident armed Vanguard submarine that is always out in the North Atlantic somewhere on duty. The Americans think we should have two of them on duty at all times, in case one is eliminated before an all-out strategic nuclear weapons attack on the UK (but that would require 8 Vanguard subs rather than 4 and twice as many missiles/nukes).
You are comparing apples and pears. Russia before Ukraine was in a stronger place economically and militarily. Also, as we now find out Putin expected Ukraine to fall as quickly as the Crimea. It was meant to be a short war but it has turned into a long attritional war which they were not prepared. Your idea of them going further to take on others this side of ten years is laughable. Putin will be in his 80's by then and likely dead/deposed.
Russia is far from a sensible country though. Its citizens are fed a diet of extreme nationalist/anti-Western propaganda from childhood, most of them live in grinding poverty and have little first-hand knowledge about life abroad. Putin has put the blame for the Ukraine war on NATO, Ukrainian Nazis etc and a majority of Russians actually believe that nonsense. Putin is likely to be replaced by someone equally psychotic and Russia has the population/natural resources to grow into its current war and massively rearm over the next 5-10 years. 10 years is not very long really. If Britain doesn't start rearming/reversing its military cuts soon then we could be caught with our pants down when Putin or his successor finally crosses a NATO red-line.
I doubt Russia would nuke us or France as that would set off a nuclear war.
Russia have talked of detonating a small nuclear bomb. I suspect they would do that in non-nuclear countries then the ball would be in our court to start a nuclear war.
I think we'd get hit with conventional missiles/bombs.
Yes, in their
"Seven Days to the River Rhine" World War 3 battle plan the Soviet Union described how it would use nuclear weapons to attack non-nuclear bases and cities in West Germany, Austria, Italy, Holland and Denmark. However, it would only use high explosive ordnance to attack targets in Britain and France (which had their own nuclear weapons) in order to avoid nuclear retaliation.
For example, Vienna was to be hit by two 500-kiloton bombs, while Vicenza, Verona, Padova, and several bases in Italy were to be hit by single 500-kiloton bombs. Stuttgart, Munich, and Nuremberg in West Germany were to be destroyed by nuclear weapons. In Denmark, targets would include Roskilde and Esbjerg. Roskilde, which, while having no military significance would be targeted for its cultural and historical significance in order to break the morale of the Danish population and army, while Esbjerg would be targeted for its large harbour capable of facilitating delivery of NATO reinforcements.
It is likely that Russia would use similar cynical tactics if it went to war with NATO today.
I'd like to add that the best way out of this situation for us, EU and NATO to take over the Ukraine government, and negotiate with Putin, even if it means creating another west/east border situation like what happened post WW2 with Germany.
We are never going to take over the Ukraine government, that would be morally repugnant and it would require going to war with them.
Putin cannot be negotiated with because he is a morally bankrupt psychopath. He only respects strength and force. You cannot appeal to his reasonable side because he doesn't have one.
He wiped his arse with the Budapest Memorandum and the Minsk Agreements, so why do you think he can be trusted to keep his word on any new agreement he makes with Ukraine?