How they mocked. My claim, in a Guardian video a month ago, that Labour could turn this election around, was received with hilarity. “Fantasy Island”, “pure pie in the sky”, “delusional”, “magical thinking”, “grow up” were among the gentler comments. The election campaign, almost everyone agreed, would be a victory lap for the Conservatives. The only question was whether Theresa May would gain a massive majority or a spectacular one. Now the braying voices falter.

Could it really happen? No prediction, in these volatile times, should carry much weight. But this we can say: a Labour win is no longer an impossible dream. It is certainly a dream, for those of us who have been waiting, longer than my adult life, for a government beholden only to the people, rather than to the City or the owners of newspapers. But it is now a plausible one.

And why not? On policy after policy, the Labour manifesto accords with what people say they want. It offers a strong and stable National Health Service, in which privatisation is reversed, clinical budgets rise and staff are properly paid. It promises more investment in schools, smaller class sizes, and an end to the stifling micromanagement driving teachers out of the profession. It will restore free education at universities. It will ensure that railways, water, energy and the postal service are owned for the benefit of everyone, rather than only the bosses and shareholders. It will smoke out tax avoidance, and bring the banks under control.

While Theresa May will use Brexit as a wrecking ball to be swung at workers’ rights, environmental laws and other regulations the Conservative party has long wanted to destroy, Labour has promised to enhance these public protections. It will ban zero-hours contracts, prevent companies from forcing their staff into bogus self-employment, and give all workers – whether temporary or permanent – equal rights. The unemployed will be treated with respect. Both carers and people with disabilities will be properly supported. Those who need homes will find them, and tenants will be protected from the new generation of rack-renting slumlords. Who, apart from the richest beneficiaries of the current regime, would not wish to live in such a nation?

Despite so many years of protest, Corbyn’s greatest strength lies in proposition, rather than in opposition

The great impediment was supposed to be Jeremy Corbyn. It is true that he failed to shine in opposition, missing golden opportunities to expose the government and contest its policies. For those of us who were willing him to take the battle to the government, these shortcomings were intensely frustrating.

But how different he has looked since Labour did what it should have done 18 months ago: propose a coherent political programme of its own. Despite so many years of protest, Corbyn’s greatest strength lies in proposition rather than in opposition: his gentle style is better suited to explaining his own vision than to contesting his opponent’s. The more exposure he receives, the better he looks – while the cameras expose May as charmless, cheerless and, above all, frit.

She won’t stand up to anyone who wields power. She will say nothing against Donald Trump, even when he peddles blatant falsehoods in the aftermath of terrorist attacks in this nation, exploiting our grief to support his disgusting prejudices; even when he pulls out of the global agreement on climate change.

She is even more sycophantic towards this revolting man than Tony Blair was to George W Bush. She won’t confront Saudi Arabia over terrorism or Yemen or anything else. Far from it: both as home secretary and as prime minister she appears to have suppressed a report into the foreign funding of jihadi groups in the UK that is said to focus on the role of the Saudi kingdom. When there is a conflict between our security and selling weapons to a despotic regime, brutality wins.

Theresa May with Donald Trump in Washington, January 2017. Photograph: Pablo Martinez Monsivais/AP

She won’t stand up to the polluters lavishly funding the Conservative party, whose role explains both her weakness on climate change and her miserable failure to address our air pollution crisis. She won’t stand up to the fanatics in her party who call for the hardest of possible Brexits. She won’t stand up on television to debate these policies because she knows that the more we see, the less we like. The party machine’s attempt to build a personality cult around her fell at an obvious hurdle: first, you need a personality.

Who, in this fissile age, would wish for a prime minister with no discernible convictions, no perceivable moral core? Who, when we need courage in government more than at any time in the recent past, wants a prime minister who rolls over to everyone from the Daily Mail to King Salman bin Abdulaziz al-Saud? Who, as we face negotiations with the European Union that will determine the future of this nation – negotiations that demand the utmost delicacy and care – wants a government peopled with buffoons, blusterers and bullies?

For many years, political enthusiasm in the UK was snuffed out by a joyless, lifeless managerialism practised by both the Conservatives and Labour. Its purpose was to reconcile a semblance of democracy with the demands of banks, corporations, US power and the offshored rich. The greed and intolerance of the press barons and their fellow tax exiles weighed more heavily with government than either political principles or the aspirations of the powerless.

There were real differences between the parties, but these narrowed as Labour embraced the neoliberalism of its opponents. The major parties became ever less willing to change social outcomes. As hope was stifled, turnout in elections plummeted. But this week, the point of voting is undeniable. The choice with which you are faced on Thursday carries more weight and meaning than it has done for decades.

By the time I walk out of the polling booth, I will have voted for four parties in 10 years: the Greens, the Liberal Democrats, Plaid Cymru and, at last, Labour. In every case, I have sought an escape from the unelected powers that govern this nation. Until now, I have voted with resignation, sometimes edging into despair. This week, for the first time in my life, I will vote in hope.

The election now hangs on whether the young people who claim they will vote Labour are prepared to act on this intention. We know that older Conservative voters will make good their promise: they always do. Will the young electors, who will lose most from another five years of unresponsive government, walk a couple of hundred metres to their polling stations? Or will they let this unprecedented chance to change the nation slip through their fingers? The world belongs to those who turn up.

Those dreams we have entertained for so long: we can realise them. Those visions of a better life that seemed impossible a month ago: they now depend on turnout and turnout alone. That unfamiliar, tingling sensation that’s been troubling you of late? It’s called hope. Don’t let them take it away from you.