Keir Starmer’s cabinet has been told to behave as if it is now “nil-nil” in the battle with the Tories, despite Labour’s landslide election win, amid warnings the party won with the support of an extremely fragile coalition of voters. The prime minister and his top team were given the warning just weeks after clinching the decisive election victory that delivered Labour a 174-seat majority. Senior aides warned that while the key voters for Labour’s win were those who switched to the party from the Tories, it was the performance of Reform UK that turned a strong win into a landslide. The warning comes with Labour preparing for the first party conference in government for 15 years. Despite the return to power, Starmer and his leading ministers have deliberately adopted a downbeat tone before what is set to be a tax-rising budget next month. While triumphalism was banned in the run-up to the election, the claim that ministers must now behave as if they are starting from scratch was delivered in a briefing to the cabinet over the summer by Paul Ovenden, a senior Starmer adviser. He is said to have told ministers that, given Britain’s political volatility, they must put Labour’s majority out of their mind and imagine that they are nil-nil in the next political race. He is also said to have stated that the huge scale of the victory was enabled by Reform UK taking 20% of 2019 Conservative voters. Labour’s landslide came despite only winning less than 34% of the vote. The revelation comes in a forthcoming book on Labour’s election victory, Taken As Red, by ITV News’s deputy political editor, Anushka Asthana. It also contains a new analysis of the impact Reform had on the result. The research by YouGov suggests that about 60 Conservative MPs would have been saved without the surge in support for Reform during the campaign. Asthana’s book reveals Labour’s internal polling had suggested it was on 37% of support as the poll approached. However, aides believe that the figure fell on polling day because some voters cast a tactical vote for the Liberal Democrats where they were best placed to beat the Tories, or felt able to vote for the Greens or independent candidates knowing that Labour was on course to form the next government. But the result has left many inside Labour paranoid about how to hold on to its winning coalition of voters when the political conditions become more difficult. Jonathan Ashworth, the former shadow cabinet minister who suffered a shock defeat in his Leicester South seat, said that political volatility was now much stronger. “I am the talking, breathing proof that there is no such thing as a safe seat. We have gone from the ‘red wall’ collapse in 2019 to a landslide victory in parliamentary seats – there is huge volatility these days and we cannot assume we will win the next general election,” he said. Academics also said that the result is that Labour’s voter coalition is far more fragile than the overall numbers suggest. Robert Ford, professor of political science at Manchester University, described Labour’s 2024 strategy as a “masterpiece of electoral Jenga” that saw the party make decisions that risked upsetting core voters, but may attract those in marginal seats. “It will not take much to bring this teetering tower tumbling down,” he said.