ince the stiff early weeks of his Labour leadership, Keir Starmer has loosened up a bit as a public figure. He talks in a more colloquial, less lawyerly way on his monthly LBC radio phone-in, Call Keir. He laughs more, sometimes at himself. Last month he appeared on Desert Island Discs, and spoke candidly about his “difficult” father and disabled mother. Especially compared to Boris Johnson, Starmer has begun to look like a rounded human being, as well as a capable one – the sort of opposition leader that party strategists and many voters consider prime ministerial. At the same time, he has tightened his hold over Labour. He likes to say that the party is “under new management” – tellingly, a phrase from business rather than democratic politics. The shadow cabinet and senior Labour bureaucracy have been cleared of potentially disruptive figures from the previous leadership. The party whip has been withdrawn from Jeremy Corbyn for his refusal to stick to Starmer’s new line on Labour antisemitism. Constituency parties have been ordered not to discuss Corbyn’s treatment. Some Labour members who have done so have been suspended. There have been sporadic protests at Starmer’s severity, including the passing of motions of no confidence in his leadership by a few constituency parties, but so far he has not been obviously damaged. Despite only having been an MP for five years, and leader for eight months, he has more power over the party than Corbyn or Ed Miliband enjoyed as leaders. Even Gordon Brown and Tony Blair had to coexist with other high-profile Labour politicians, who had sometimes very different ideas about what the party should do. But the scale of Labour’s defeat last year, the apparent collapse of Corbynism, and the party’s desperation to get back into power, seem to have given Starmer a free hand. Centrist commentators like what he is doing with it. In last week’s New Statesman magazine, one of Blair’s former speechwriters, Philip Collins, praised Starmer for his “strict message discipline” and being “prepared to do what it takes to win”. He advised Labour’s leader to ignore the “vapid demand for a ‘vision’” from critics who say he has yet to lay out the purpose of a Starmer government, or even any policies. After the failed, ever more leftwing experiments of Miliband and Corbyn, the centrist argument goes, Starmer’s leadership is a return to political realism. But this is a limited, even counterproductive form of realism. By heavily emphasising winning power over thinking about how to exercise it – about how to change British society and gain prolonged national support for it – centrist realism serves the party and the country much less well than its advocates imagine. Even in these narrow terms, it’s open to question how promising Starmer’s leadership really is. His admirers make much of Labour’s recovery in the polls under him, from 11 percentage points behind at last year’s election to about level with the Conservatives now. It sounds impressive, until you realise that every Labour leader since 1980 – even the hapless Michael Foot – has been about level with or ahead of the Tories after their first eight months. Many British voters habitually make a show of considering new Labour leaders, before rejecting them at the first opportunity. When Labour does win, the centrists’ excess of caution and lack of vision can make Labour governments less significant than they should be. Blair and Brown ruled Britain with big majorities for 13 years: longer than Margaret Thatcher, longer than the motley assortment of Tory premiers since 2010. Yet it’s hard to argue that New Labour changed Britain as much as these Conservative governments. Many of Blair and Brown’s welcome expansions of the caring parts of the state were undone by just a couple of years of Tory austerity. Nor did New Labour’s coalition of voters prove very enduring. The fact that Blair’s old seat of Sedgefield in County Durham fell to the Conservatives last year was a failure of Blairism as well as Corbynism: the Labour majority there started shrinking long before Corbyn became leader. If the party is to recover for the long term, and if any Starmer government is to be more than just another Labour interlude in an essentially Tory era, then what it means for a Labour leader to be realistic needs a more ambitious definition. A Starmer government will need to enact reforms and create political loyalties that outlast it. Clement Attlee’s postwar administration managed both. Although it lost power after six years, most of the new institutions it established, such as the NHS, and most of the expanded Labour vote Attlee had attracted, remained intact through the Conservative governments that followed. When Labour revived under Harold Wilson, he had a lot to build on. Starting in 1964, he won four of the next five elections, despite leading a series of flawed governments, and was taken seriously when he claimed that Labour had become “the natural party of government”. Those days seem a long way off now. And worrying about whether Starmer will ever be able to make the same claim feels in many ways very premature, when the Conservatives still lead in some polls – thanks to a minority of voters who appear willing to tolerate any Tory mistake – and the next election could be four years away. Thanks to the pandemic, Starmer hasn’t even made a leader’s speech to a live audience. But he does have a big opportunity. He’s become opposition leader at a favourable stage in the electoral cycle. Whenever the election comes, it’s likely that the government will seem tired. In power for too long, and short of fresh ideas and talent, the Tories could conceivably lose not just one election but several. It happened when they ran out of steam in the 1990s. Could Starmer take advantage, and achieve something lasting? When he ran for leader, he produced a highly successful video emphasising his leftwing past. He also made 10 pledges, many of them quite radical, such as “no more illegal wars” and putting “public services” back “in public hands”. The one thing his centrist admirers and leftist critics generally agree on is that he made these pledges to win over the leftwing Labour membership – they’re not necessarily a guide to what he really believes, or would like to do in power. Yet there’s just a chance that Starmer can be persuaded to become more ambitious in his policy thinking. He is still a relatively unformed politician. On Desert Island Discs he said: “As I’ve grown up, I’ve learned the power of saying, ‘I don’t know. Let’s have a look at that.’” If he ever becomes prime minister, like Attlee in 1945, Starmer will face British and global problems that are too large for the usual Labour caution in government. He might surprise us. Andy Beckett is a Guardian columnist