s I write, no puff of white smoke proclaims a done deal. Boris Johnson may drag out his excruciating psychodrama a few days longer, postponing the moment his Brexit is exposed as a sham. The infinite patience of EU negotiators never flags, as they wait for him to succumb to the inevitable, like adults waiting for a child having a tantrum to calm down. In the final charade, Britain dances its defiant haka with tongues out at those across the Channel, still displaying bogus no-deal bravado. “Cabinet backs Johnson over no-deal Brexit,” splashed the Sunday Times. Of course it does: this Brexit moment is the sole reason most of this ship of fools ever got their feet under that august table. Today’s Daily Mail declared that “Bullish Boris” was “ready to walk away”. The Metro had: “Frosty the NO man: UK’s chief negotiator holding out.” The Express went with: “PM: No deal if we can’t take back control.” One pathetic minister bleated: “We hold all the cards.” Brussels isn’t quaking in its boots: the EU’s team are well used to Brexit sabre-rattling. They sigh politely at Johnson’s bad faith in pushing through his law-breaking internal market bill as negotiations approach the endgame: they know the UK will sign a trade deal because it must. Trading with the single market always meant following European single market rules. It’s our choice to make, but now with no seat at their table to change those rules. Forget a “Canada deal”: our trade with the EU is 10 times Canada’s. As the EU’s largest outside trader by far, if we flood their market with lower standard or unfairly subsidised goods, we risk doing greater damage than anyone. I presume Sunday night’s leaking of the official “reasonable worst case” scenario for no deal was timed to frighten Brexiteers who want to leave at any cost: it risks a reduction of between 20% and 40% in medicine imports, fishing boats clashing at sea, fresh food supplies cut, low-income households hit worst by price rises, oil shortages, 20 local authorities collapsing under costs, and between 40% and 70% of trucks travelling to the EU not having paperwork ready, while public protests overstretch the police. All these run alongside the old familiars: tariffs would kill off the car industry, farming, fishing and finance, while at the same time creating a hard border in Ireland and earning the enmity of the new US president. That is why Johnson will sign, but the moment pen touches paper, watch the nuclear explosion among those who put him in Downing Street. He will finally have to betray his Brexit no pasarans, while grinning gargoyle Nigel Farage sharpens his teeth, anticipating his next comeback. “There’s no reasonable negotiation on offer,” he tweeted. Johnson must sell the deal to both Brextremists and to moderate leave voters, either as the hardest of crash-outs or as the smoothest for future EU relations – but not both. His bare-bones, worst-of-all-worlds deal will please no one. He will proclaim it “fantastic”, “world-beating” and all the rest of his limited vocabulary of weary superlatives. The only upside is avoiding the apocalypse the Tories pretended was “better than a bad deal”. Labour’s task is easy: this bad deal excludes the vital 80% of the UK economy reliant on services and finance. The Road Haulage Association expects “between shocking and catastrophe”, the National Audit Office warns of “widespread disruption”, while the British Retail Consortium calls this “the biggest imposition of red tape that businesses have had to deal with in 50 years”. Every effect of this Brexit belongs to the Tories: this day of reckoning may break them. Where is the promised soft landing in sunlit uplands? Instead of “exact same benefits”, there will be none. Damage stretching years ahead may merge with Covid, but by 2024’s election those lost Labour seats will not rank Brexit as a reason to vote Tory. Polling finds red wall seats backing away, with Labour ahead in 36 of the 45, and Brexit is already outweighed by indignation over Dominic Cummings’ trip to Barnard Castle and Covid mishandling. In voting on the deal, remember this isn’t Labour’s fight. The final battle is between Tory Brexiteers – the betrayers and betrayed – tearing into each other over an ideal Brexit that never was. Labour’s task is to ask where the Tories’ good deal went. To vote for this economy-wrecking deal risks owning it: better by far to abstain. Keir Starmer has the chance to make the speech of a lifetime, describing the betrayal of all who believed what Johnson promised. He can list the failures – and show the way to rebuild out of this chaos. Remember this vote only concerns political tactics, not high principle. Whether Labour abstains or votes to save the country from no-deal calamity, it must try for unity. A minor Labour split over strategy should not be allowed to steal any airtime from the resounding crash of the Tory party falling to earth, its delusions shattered. Polly Toynbee is a Guardian columnist Join Anushka Asthana and journalists Michael Safi, Aamna Modhin and Oliver Laughland for a Guardian Live event on the biggest stories of the year, from the pandemic to Black Lives Matter and the US election. On Tuesday 8 December, 7pm GMT, 8pm CET, 2pm EST Book tickets here