Keir Starmer’s caution may be frustrating, but it’s right. Voters no longer trust big promises

‘Keir Starmer has turned around a dysfunctional and bitterly divided party and brought it to the threshold of power.’ Starmer visits Sydney Russell school in Dagenham, east London, on Monday. Photograph: Gareth Fuller/PA

Prime minister might not be the hardest job in Britain, but it combines the highest level of responsibility with the lowest barrier to entry for inadequate candidates. You don’t get to be a rocket scientist, for example, by reckoning you’d be good at it and persuading enough people to give you a go.

But rocket scientists don’t need to win a popular mandate to take tough decisions. They don’t need to be likeable on telly. Running a government is almost impossibly difficult because the skills necessary for winning power are unlike the ones required to use it well. Campaign wizards can lack the temperament to be competent managers. Shrewd judgment doesn’t always express itself in memorable phrases; which brings us to Keir Starmer.