"Nukes are, well, the nuclear option, so they are of little use except in extreme circumstances..."
Very true. To clarify matters, we might ask ourselves: against which nations are the UK's thermonuclear weapons potentially useful today? (I hope no one is going to suggest that they frighten ISIS, for example).
Russia? If so, why? Russia's interests do not clash with the UK's anywhere on earth - quite the contrary, it is in our best interests to live in peace with the Russians. Whereas we lived in fear (rightly or wrongly) of the USSR invading Western Europe, Mr Putin has shown supernatural restraint in not even invading Ukraine after 750,000 of its citizens fled to Russia for safety. As for Georgia, he was "in and out quickly", as the saying goes.
China? Likewise, only if possible even more so. The Chinese are quite extraordinarily pacific (especially compared to other superpowers that shall be nameless), and what's more they are very nearly on the far side of the world.
India or Pakistan? I don't see it. They're not quite so peaceable, but they have no quarrel with us, and we should make sure that remains the case.
Israel? Not really - they would probably get in a first strike, and they have far more missiles and warheads.
And as for France, that's just childish. We should be content just to go on annoying them.