Boris Johnson’s ambition to succeed David Cameron is scarcely less disguised than Gordon Brown’s was to displace Tony Blair, although it manifests itself in a more cheerful form. The only real argument about Johnson’s leadership bid is the timetable. Quitting early as Mayor of London is not necessary; indeed, it would be harmful to his prospects. The rules are clear: a new mayoral election must be held within 35 days of the incumbent resigning, unless his term has only six months left. Such a by-election would not be welcomed by the Conservative Party. In any case, why would Boris wish to quit early? He loves the job. Some talk as if completing his term and then going on to become prime minister were mutually exclusive. Boris will be just 51 when he is due to stand down in 2016.
If the Conservatives win the next election and Cameron remains in Downing Street then the timing would be about right. Boris would need to wait around a year or so for a suitable by-election. Then, as an MP, he could take another year to schmooze the Tory backbenchers, many of whom he won’t know. This would also give him the chance to make some good Commons speeches. In his seven years as MP for Henley he proved a disappointing parliamentarian. That is something he needs to rectify. By 2018 or 2019 it might well be that Cameron will be ready to stand down, rather than seek a third term. He would need to give a new leader a chance to establish himself before the 2020 general election. So Boris could become prime minister in 2020, at the age of 55. With any luck, his trademark blonde hair won’t yet have turned white.
Should Ed Miliband be prime minister, however, the Tory leadership manoeuvrings could be more messy. Cameron might stand down if he loses in 2015, and a new leader would be in place before Boris became an MP. A leadership challenge by Boris in 2017 would be one scenario. Another would be that he seeks a by-election to become an MP a few months before his mayoral term comes to an end. There is a precedent: Ken Livingstone was Mayor of London and MP for Brent East for a year before the 2001 general election.
There would be a strong case that Boris as Conservative leader in 2020 would be best placed to avert a second term for Ed Miliband. A recent YouGov poll suggests that switching from Cameron to Boris would slash Labour’s lead from 8 per cent to 1 per cent. Yet Cameron is a relatively popular politician. The lead Boris would enjoy over any rivals likely to succeed him might be larger.
Fewer and fewer people dismiss the notion of Boris becoming prime minister as implausible. The success of the London Olympics showed his seriousness and commitment in delivering a big project, and gave him a national profile. Polling undertaken by Lord Ashcroft shows his popularity is not confined to the capital. But completing two terms as Mayor would leave him with a formidable London power base. His brother Jo is a London MP; perhaps he could provide the necessary by-election, thus offering a contrast of fraternal solidarity to the fratricidal behaviour of the Milibands. So a return to machine politics is likely, something Boris excelled at on a micro scale at Oxford. London has a disproportionate number of marginal seats, and the Conservatives need those seats to win the country. The London factor in the 2020 general election could make all the difference.