That’s not a helpful comparison. Britain is an island with, needless to say, fixed borders, and, within that, England is just about the oldest nation state in Europe. Ukraine has existed an independent entity since 1991 and only for very brief periods before then. It is a separate nation rather than an appendage to Russia or Poland but I don’t see the reason for an absolutist view of its territorial scope when the price is so high. If they emerge without Crimea and potentially without the Donbass but with a meaningful NATO security guarantee and a roadmap to EU integration (and without their country being razed while we cheer them on from armchairs in Western Europe), that is a big strategic win in the grander scheme of things.