Churchillian echoes from Volodymyr Zelenskiy stiffened the sinews and summoned up the blood of the House of Commons: “We will fight in the forests, in the fields, the shores and in the streets.” Each of us, distant spectators of unfolding catastrophe, tries to imagine those missiles pulverising our streets, willing Zelenskiy and his country to survive. But, being human, even in our darkest hour we cleave to another wartime maxim attributed to Churchill: never let a good crisis go to waste. Look around in Britain and you can see all sides scurrying to make good use of this. You could call it cynical opportunism – or if you have a more benign view of human nature, it’s a natural impulse to rescue some hope from Putin’s hell. Start with the left, the internationalists, the progressives, the social democrats, living for ever in hope that events will prove us so incontrovertibly right that more people will swing our way, ending the electoral hegemony of Conservatism. The first light in the tunnel: Britain is back close to Europe. Without gloating or saying we told you so, it is worth pointing out that this war proves, beyond geography, that Britain’s destiny is European. In defence, as in trade, we belong inalienably to this democratic neighbourhood. Europe is us, physically, politically and psychologically, while “global Britain” was a vacuous nothing. Ukraine yearns to join, so ask them if Brussels is the “EUSSR” of that crass Brexit slogan. Last week, the EU invited the foreign secretary, Liz Truss, to its Foreign Affairs Council meeting for the first time since Brexit. In a double somersault, Truss called it “vitally important” that the UK and its allies “show complete unity”. Most who caused Brexit fall silent, leaving only the Europhobic fringe sounding off: Steve Baker, of the European Research Group, called for Article 16 of the Northern Ireland protocol to be triggered “immediately” while on a visit to Belfast last week. But fighting the EU over sausages on the Irish border is far out of step with the times. The spasm of xenophobia that was spread by the Brexiteers has lifted, too. A YouGov poll has found three-quarters of voters want Ukrainians admitted immediately without visas. Johnson will be dogged by the shame of Tory mean-spiritedness as other countries threw open their borders. The divide between climate activists and petrol-heads has been deepened by this war, too. Ending oil and gas dependency is now clearly a defence as well as a climate priority; the need to accelerate renewables, home insulation and heat pump installation, to make net zero reachable has never felt more urgent. Look, the possibility of an energy-generating barrage on the Severn estuary is back on the agenda. Energy independence has become a security issue, says Adair Turner, chair of the Energy Transitions Commission, calling on consumers to defeat Putin. Cutting road speeds to 55mph and turning down central heating would “make an immediate impact” on Russia, he says. But against him stands FairFuelUK, “the real voice of the UK’s 37m drivers”, seizing its chance for petrol tax cuts after years of frightening the government out of fuel tax rises. Thirst for gas and oil exposes western dependence on other dictators – the Saudis, Qatar – while US emissaries are suddenly visiting the outcast Maduro of Venezuela. “Climate sceptics” and oil company-funded pressure groups seize on the new energy gap as their big chance, too. “Frack us out of the fuel crisis, Boris!” – the Mail reports as Craig Mackinlay rallies his Net Zero Security Group of Tories. Johnson always appeases his right: sealing off shale gas wells does “not make sense,” he says now, never mind the years it would take to reap any supposed benefits from the wells. Nigel Farage is on the move, too, calling for a referendum to kill off net-zero targets and the “ruinous” green agenda. As for the prime minister, Ukraine is his hope of salvation: surely, war is no time for a leadership election over parties long forgotten? War may save his skin when the police and Sue Gray eventually come knocking. Watch the retreat of erstwhile Tory enemies such as Rory Stewart: “I think he’s a terrible human being. I think he’s a terrible prime minister, but I think he’s done OK on the Ukraine crisis.” Here’s another hope: war may stop the government’s assault on the BBC, Britain’s greatest global influencer. How like Putin does Johnson want to be? Another hope is for an end to the London laundromat hiding money filched from other citizens. But will the City be cleansed or just whitewashed? And there’s the economy: as the war deepens the cost-of-living calamity, the chancellor can’t avoid a U-turn in his spring statement. Tory MPs join Labour in calling a halt to April’s unequal national insurance rise. The business secretary, Kwasi Kwarteng, says people are “willing to endure hardships” in solidarity with Ukraine. But will the public demand equality in who bears that pain? Millions of the hard-pressed will join battalions of the absolutely poor neither heating nor eating unless this talk of “sacrifice” summons genuine wartime fairness, tapping into wealth to guarantee enough for everyone. Will we all be in this together? The old tug-of-war between tax rises and spending cuts is unabated, the likes of Roger Bootle, chair of Capital Economics, saying defence spending may have to rise to 4% at the expense of cuts. But from which already starved services: the NHS? Schools? Border Force? The right never says. The chancellor needs to eat the words in his ill-judged Mais lecture promising tax cuts. Putin may succeed militarily in the near future, though he may never hold down Ukraine – that vast, rebellious country. On the home front, the question is what the war will do to us. The left always lives in optimism that fairer and greener choices will prevail, but the left is also used to disappointment. The fight is on to see if this brings out the best in us, and not the worst. Polly Toynbee is a Guardian columnist