As polling day rapidly approaches, the strategic choices facing the electorate have been illuminated by the Conservative campaign. The willingness to fabricate and tell outright lies is a new departure in British politics. Politicians have always attempted to present the most favourable facts and to explain away and minimise problems. But in this election, the Tories haven’t tried to excuse their record but to nakedly lie about it. They have deliberately sought to stoke controversy and to confuse voters about facts, from mendacious dossiers to fake fact-checking. This approach to politics makes the spin of the New Labour era seem rather quaint and tame by comparison. Indeed, the cynical adoption of such manipulative methods by the Conservative political elite is nothing short of disturbing.

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There is a dangerous intersection with the way social media has reshaped political reporting. With faster and faster news cycles, journalists are under pressure to be the first to break new information to their vast social media followings. But this approach is unsustainable in an era when political operatives are prepared to fabricate stories – from the hurricane of bluster that emerged from Downing Street before the election, to the false claim by the Conservatives that a Tory staffer had been punched by a Labour activist just this week. The lesson is that journalists need to slow down, step back and interrogate what they are told from a sceptical stance.

Just as journalists need to take a step back from the cacophony of the campaigns, so too should voters. The last days of the campaign have revealed the decline and death of conservatism, usurped by the radical right. The Tories no longer claim that Brexit is the route to a better Britain, but instead claim that they are the only solution to the calamity and chaos of their own creation. They have become even more extreme on immigration – no longer simply stoking fear that more immigrants would arrive, but attempting to turn neighbours into strangers by asserting that EU migrants had for too long been able to “treat the UK as if it’s part of their own country”.

So in its methods and its message, the new Tory political formulation is strongly redolent of what the political theorist Hannah Arendt described as the “alliance of the elite and the mob” in her landmark work the Origins of Totalitarianism. It is not an accident but a deliberate strategy. And as a result, it demands a strategic response. The only way to resist this dark turn in British politics is to establish a new alliance of the left and the centre that is capable of denying the Tories a majority. The best way to encourage all those that abhor Johnson’s politics to vote tactically is for them to understand that it is part of a wider strategy.

What is challenging is that for such an alliance to form, the centre must accept the leadership of the left. This is not simply a pragmatic conclusion because Labour’s leaders are long-time leftists. It is more fundamental than that. Only the left has the answers to the problems in the economy and society that exist today. The scale of the challenges – from climate breakdown to inequality – demands a scale of response that a managerial centre with its scepticism of structural change cannot offer. Moreover, a decade after the financial crash, the centre has comprehensively failed to renew itself, having allowed resistance to Brexit to fill the void where politics should belong. Only the left offers the answers to today’s problems.

But the centre of politics is hamstrung by a strong cultural resistance to acceptance of left leadership. After dominating politics for a generation, a sense of entitlement courses strongly through centrists, many of whom are yet to find acceptance for their diminished status. At the same time, the more sectarian parts of the left have reasserted themselves, reserving special venom for centrists as payback for their own marginalisation for decades. These dynamics have been most obvious over Brexit, where remainers realised too late that they needed the Labour party, and the Labour party realised too late that it needed remainers. The left and the centre need a last-minute reconciliation at the ballot box.

As voters go to the polls, they must be aware of how high the stakes are in this election. There is a fundamental choice about the future direction that will echo for decades, not just whether Britain stays or leave the EU, or the immediate risks to the NHS. The rise of hard right politics has created a political emergency where the strategic response needs to be a more pluralist politics of broad alliances that are capable of defeating the clear and present danger. On Thursday, a decision to vote tactically is to embrace a broader strategy for a decent, tolerant and progressive Britain. Only if the left and the centre join forces will the radical right be denied a generational victory.

• Tom Kibasi is a writer and researcher on politics and economics