'The UK' doesn't equate to its population
Even should the UK become formally at war with Russia and with other places where decency lingers, don't conclude that it's the British people against the dastardly foreigners.
Warfare remains the preserve of the monarch, among other 'residual powers'. In practice, that means, war is waged by a powerful self-perpetuating cabal within the Privy Council. These days, monarchs are employees of the Council who can be dismissed if they become uppity.
Parliament, had negligible say in foreign policy, defence policy, and in declaration of war. Given that universal franchise representative 'democracy' is a nonsensical decision-taking tool, perhaps Parliament's exclusion is prudent. PMs, and Secretaries of State, automatically receive membership of the Privy Council, but in recent decades none qualify for inclusion within the inner cabal; one glance at the shabby crowd explains why.
The interesting question is whether plebeians (and many of their betters) are as insular, ignorant, conformist, and in thrall to pageantry, as their forebears in WW1 and WW2. Shall they rush forward for 'King and Country' after shallowing a yarn about existential threat or 'principle' worthy of sacrifice of life? WW1 was a nonsensical conflict among mainland European powers; what Kipling called, 'the lesser breeds' to be found in mainland Europe, and elsewhere, should have been left to stew in they own juices; in the aftermath, Britain could have picked through the pieces for tasty morsels instead of bankrupting itself.
Britain's participation in WW2 is portrayed as leading a noble cause (until the USA joined in and won the war) - no mention of Russians. Yet, Germany initially was no threat to the UK, and need never have been. Germany's "gangster regime" could have been left to implode naturally. Once again, Britain would not have been bankrupted. Moreover, the Japanese could have been left to pursue their grudge against the USA.
Of course, powerful factions, especially bankers, benefit from warfare: rarely do ordinary people. The common man is left with 'Remembrance Ceremonies' for people foolishly caught up in schemes they didn't begin to understand.
One might have thought that post-WW2, the expansion of eduction would give rise to a more savvy population capable of resisting demand they sacrifice themselves for empty causes profitable to other people. Not so, and 'enlightened' folk, from a stock which in later decades would embrace 'woke' and transgender nonsense, ended selective education and ruined further and tertiary education. Additional damage to tertiary education arose from a political cadre opposed to the 'enlightened', but equally crass and prone to impose ideology (in their case neoliberal ideas including making universities and scholarship 'businesslike').
Nowadays, the mass of the population is ill-educated, and punchdrunk from 'austerity', from an idiotically managed Covid-19 local epidemic, from more austerity resulting from that, and from yet more austerity flowing from inherently incompetent NATO's silly attempt to weaken Russia by conflict on the Ukraine with an end view to Balkanising Russia and exploiting its resources. Meanwhile, income and wealth disparities have mushroomed.
The upshot is that a vast majority of Britons, soaked relentlessly by propaganda, would go along with plans, fronted by Mr Starmer, by Ms Bad Enoch, or by Mr Farage (with Yaxley-Lennon in tow) calling upon sacrifice of life to preserve Western 'democracy', 'freedoms', and 'values'.
