There are at least three reasons some Tories are willing to consider seriously alternative candidates as their next leader. The first is the timetable. Let us make some hefty assumptions and say that Britain votes to remain in the European Union, and that the Conservative Party, despite its painful split over Europe, permits Mr Cameron to remain in office until close to the 2020 election before handing over. The next leader, therefore, will be the party’s nominee for the premiership from 2020 to 2025, and quite possibly for another five years after that. Mr Osborne, Mr Johnson and Mrs May have already been at the forefront of politics for almost a decade. In our fickle age, with the electorate’s attention-span made skittish by smartphones and 24/7 news, could any of them, even the quixotic Mr Johnson, hold the public gaze until 2030?