Labour may win big under first past the post, but it is morally obliged to bring in a fairer system | Polly Toynbee

In one great whoosh, the country looks set to hose away this despicable government on an outflow of its own sewage. Kicking the bastards out is what democracy does. That seems to be the primary will of the people now.

To eject them, large numbers will hold their noses and vote for parties they don't support. Nearly 40% of people say they would consider it . More voters, say pollsters, know how to circumvent an electoral system designed to deny people a vote for their preferred party, preventing new parties from arising. We are so used to tactical voting as part of the system, we forget it's a democratic abomination.

I hope vast numbers of people do it, because first past the post makes this the only way to express their prime intent. Readers can go to the crowdfunded website tactical.vote or Best for Britain's tactical voting guide to keep out the Tories in their area. Or progressives can swap a useless vote in a safe seat for one where it will count, as organised by Compass , collecting vote swaps for candidates supporting proportional representation (PR).

Labour's win would be well deserved, the most-trusted party earning votes to change the wretched state we're in, with Starmer boasting an approval rating of +16 to Sunak's -25. Yet this time the result may be the most unrepresentative ever. Labour could win "roughly 72% of the seats in parliament on about 42% of the total vote", according to the FT's projection from tracking 46 polls.

Forget the "supermajority" nonsense: a small majority delivers the same absolute power as a massive one. But the disproportion means at the last election 70% of votes were wasted , cast for losing candidates or piled up for winners needing no extra votes. British bad governance comes from one-party rule, with violent policy swings between the two parties: this was the most extreme government in modern times.

Now comes the best chance of electoral reform. The public backing for PR is at 45% , compared with only 26% for the current system. Many of the shadow cabinet have backed PR, with the others undeclared as yet, with only a few older members against, says Laura Parker of Labour for a New Democracy. Backed by 83% of Labour members , the party conference supported PR in 2022 , and most unions are now backing it (including Unite, Unison and Usdaw). Younger and newer MPs are keenest: Kate Blake, likely to win Cities of London and Westminster, who I followed last week, is a typical pro-PR campaigner. Keir Starmer has seemed in favour before, saying in 2020 that people "feel their vote doesn't count" , but he wisely kept it out of the election campaign: the Tories would seize any chance to distract from the cost of living and the NHS.

If the result is grossly disproportionate, Labour would have a moral obligation to voters to bring in a fairer system: it couldn't be called gerrymandering when Labour had benefited so much from first past the post. Weak but long held-up reasons for opposing reform were burnt away in the turmoil of recent years. Who can defend first past the post as providing "stability" after the tragicomedy of five PMs in eight years, and scores of minsters whizzing through revolving doors? Parliament was unlawfully prorogued, Boris Johnson in sole control of a Brexit deal. The Safety of Rwanda Act made truth whatever a single party majority says it was. The stablest democracies use PR .

Ah, but we keep out the extreme right: Nigel Farage lost in seven general elections. But instead small groupings denied by the system, such as Militant in the old days, move to take over main parties. Hard-right Ukipin-spirit figures such as Suella Braverman, Priti Patel, Jacob Rees-Mogg captured the Conservative party. Braverman advocates an alliance with Reform, inviting Farage in: members could elect him leader. How would people feel at giving him sole power on a minority vote?

Besides, barring small parties forces everyone to choose between two clumsy de facto coalitions. There needs to be a socialist party and a pro-EU one-nation Tory party. The real coalitions enabled by PR oblige smaller parties to engage realistically with actual government, unlike Reform and the Greens' tempting fantasy manifestos.

If Reform wins far fewer seats than its vote share suggests, Farage will relish the grievance, demanding voting reform – and he will be right. Look around Europe and don't imagine we are divinely safe from extreme populism. Unreformed, we will be highly vulnerable: look at the US's two-party calamity. Labour should move fast to deny Farage a Trump-style "I was robbed" platform. Set up a royal commission backed by citizens' assemblies and enact a proportional system before the next election. It was in Tony Blair's manifesto; he commissioned but never enacted Roy Jenkins's plan for reform, which remains a good blend of keeping MPs attached to constituencies while adding proportional balance.

Whisper this in Starmer's ear, as to a Roman emperor. Remember all governments must die. Remember when the two-party pendulum swings, one day the opposition will thunder in and dash away your achievements: Sure Start's protected funding was gone, Every Child Matters ripped out and tax credits shredded in 2010 by George Osborne. Stability comes from a measure of consensus in coalition shifts, not oppositional rampages of revenge such as Trump threatens. Labour would govern better with some pressure from the Greens and Liberal Democrats. Rejecting the hubris of victory, Starmer should embrace this as a key legacy.

But right now, understand the rules of the game. Vote for whichever progressive party can oust a Tory. It's good to see that, in some places, Labour people have been canvassing for Lib Dem candidates . With so many undecideds among former Conservatives, fear the shy Tory vote.

Don't assume a Labour win, but as Starmer says : "If you want change, you have to vote for it.". Don't be deflected by seductive manifestos from parties without a chance where you live. And when it's over, get campaigning for electoral reform – so you never again need vote for a party not of your choice.