By rights, the United Kingdom should be firmly in the midst of what some politicians call a “change moment”: one of those periods when the demise of a government and its way of thinking becomes absolutely inevitable. Examples from the past are easy to cite. In some cases, such as 1945 and 1979, the change has come to be seen as almost revolutionary, marking the point at which the country was pulled away from an old set of certainties and pushed somewhere completely new, with all the sound and fury that implies. In others, such as 1964, 1997 and 2010, regime change has been important, but not quite a matter of one historical period giving way to another: a matter of serious shifts, perhaps, but not quite the kind of deep transformations of society and the economy that historians see as unquestionable milestones. As this strange, chaotic summer unfolds, the scent of huge political drama is in the air. If the old adage is true, that governments tend to lose elections rather than oppositions win them, many of the preconditions of a change moment have easily been met. Boris Johnson’s broken, flailing, institutionally stupid government is clearly in freefall. Loud talk of Tory plots against the prime minister are now an inbuilt part of the weekly political cycle, revelations about Johnson’s conduct extend into the distance, and instead of a coherent agenda, he and his allies have only endless panic and nasty opportunism. I have spoken to enough voters lately to know that millions of people’s view of the prime minister as a liar and amoral chancer is now immovable. At the same time, there are signs of changes that run deeper and wider. The pandemic has seriously disrupted longstanding assumptions about the reach of the state and people’s relationship with it. The government’s rank incompetence has surely tested our absurdly centralised system of government to near-destruction. The fragile mixture of negligible inflation and insanely low interest rates that just about sustained post-Thatcher economics after the crash of 2008 has finally imploded. By way of proof that something fascinating might be afoot, consider the sudden rise to prominence of the RMT’s much-admired general secretary, Mick Lynch. Until last week, almost the entire political and media class – including the Labour frontbench – had assumed that a majority of the public would always be hostile to strikes, and that any trade union leader set on industrial action must always be treated as a pariah. The way Lynch has shredded those prejudices by calmly stating basic facts suggests that our cost of living crisis is rippling through politics in ways that some people are only just starting to understand. And yet. The public mood is complex, almost to the point of being confounding. During the week of the two recent byelections I spent time in Wakefield, where the Labour party was getting very excited about retaking a seat that had been a casualty of Johnson’s demolition of the “red wall”. But plenty of people I met, including those with direct experience of our mounting social emergency, were hardly full of enthusiasm for Keir Starmer and his party. It was not hard to find others who, albeit grudgingly, were sticking with the Tories. On the day, turnout was under 40%. Meanwhile, the Lib Dems’ jaw-dropping overturning of a 24,000 Tory majority in Tiverton and Honiton showed that some of the most potent aspects of this year’s anti-Conservative mood have nothing at all to do with the official opposition, highlighting something that has been obvious for at least two decades: that the left and centre-left have become splintered and pluralistic, something only camouflaged by our crooked voting system. Clearly, the current combination of tectonic shifts and Westminster inertia highlights Starmer’s inescapable shortcomings. One of the most maddening aspects of life in 2022 is that just as the government has no plan, the Labour leadership seems to have no story about modern Britain and how they might change it. But we should also bear in mind much more fundamental realities. Whoever is in charge of the Labour party, it has almost no realistic chance of winning a Commons majority at the next election. To do so would require taking seats it has never won before, even in 1997. Scotland has long since wrested itself out of Labour’s grasp. In sizeable chunks of England, politics is once again split between the Tories and Lib Dems (note to any testy Labourites: yes, they went into coalition with the Tories, and deservedly bear the bruises – but your party took the UK into the Iraq war). In local government, the Green party is an increasingly formidable presence, underlining the fact that any meaningful progress on the climate crisis will necessarily involve its energy and ideas. This column was written in a caravan at the Glastonbury festival, where each day has seen packed political debates in the big top known as the Left Field. On Saturday, an event titled Politics in Crisis was addressed by Labour’s Greater Manchester mayor, Andy Burnham, who arrived full of vim and optimism, bearing a three-point plan for transforming the UK’s system of government as a precondition of even starting to align politics with the mounting need for big social change. Britain, he said, needs a proportional voting system. The House of Lords is a farcical offence to democracy, and should be replaced by a senate of the regions and nations. Power needs to be taken away from Westminster, and thoroughly devolved. The next election needs to mark a change moment along the lines of 1945 or 1979, but “if our political parties carry on with business as usual, it may not happen”. There was one sop to old-fashioned Labourism: his insistence that he was firmly against any electoral pacts. But the UK’s awkward and fractious family of progressive parties, he insisted, needs to begin “cooperating now on a programme for political reform”. The crowd loudly endorsed what he said. When they were asked whether they had ever switched their votes between parties in order to defeat the Tories, the vast majority raised their hands. Here, it seemed, was the living proof of something the Green MP Caroline Lucas once crystallised in a very Glastonbury-esque metaphor, which briefly became a rallying slogan for the trailblazing multiparty pressure group, Compass: the fact that the politics of Labour’s old-fashioned big tent is being superseded by what she called a “progressive campsite”, in which cooperation will be given, and everyone will have to acknowledge that no one party has the right to monopolise power. Herein lies the solution to this summer’s mismatch between politics and reality, and the key to something much more urgent – the end of a rotten, desperate, dangerous government, and an era that is unravelling in front of our eyes. John Harris is a Guardian columnist