This week’s Spectator charts Boris Johnson’s return to Parliament – and examines the network of MPs already helping him get there. You’ll have to wait till tomorrow to read Harry Mount’s piece, but here’s a preview, examining where the Mayor could stand as an MP.

Boris Johnson has spent an impressively long time dodging questions about whether he is going to stand as an MP in 2015, and where. He manages to do this by pulling a special bewildered face, as if he’s just an innocent chap who finds himself inexplicably in a spot of bother, rather than someone who has been leading everyone on about his political ambitions for far too long.

But in the next few weeks, his secret parliamentary campaign team (and there is one) expects him to pick his constituency. The Tories need a decision by the beginning of September, as an announcement any closer to the party conference will overshadow David Cameron’s own plans to talk about the manifesto, rather than watch hopelessly as cameras and journalists trail after Boris, asking the same question over and over again.

Uxbridge, where former deputy chief whip John Randall is standing down, is the favourite, with a 11,216 majority. The local association says it will make a decision in mid-September. Boris has promised to see his second mayoral term to its close in 2016, and Uxbridge would certainly help him do that, as it is at the end of a Tube line. But other seats are in play, too. His agents in Parliament say all those being considered would be compatible with him continuing to serve as Mayor.

Other seats include Hornchurch and Upminster: the current MP Dame Angela Watkinson is 72 and her 16,371 majority looks pretty cosy. In Hertsmere, the local association booted out its sitting MP, James Clappison, this summer, apparently for nothing more egregious than that he wasn’t very glamorous. The word in Hertsmere is that the local Tories want a higher-profile figure to defend the Conservatives’ 17,605 majority than Clappison, who was very good at attending constituency events, but an unknown on the national stage.

Boris is, of course, the opposite — although Hertsmere Conservatives should be careful what they wish for, as someone does still need to turn up to those thankless constituency events every once in a while, and the Mayor of London will not have the same amount of free time at his disposal as unglamorous Clappison.

He could also take the place of party grandees in safe seats such as Sir George Young’s North-West Hampshire (majority 18,583 but already selected for Boris’s deputy, Kit Malthouse), or Zac Goldsmith’s seat in Richmond Park (which has a slightly hairier 4,091 majority). Sir Peter Tapsell once said he was keeping his Louth and Horncastle seat ‘warm for Boris’ to sweep up the 13,871-strong lead, but the commute to London might be a bit of a stretch for a serving directly elected Mayor of London and a candidate is already in place. Once Andrew Lansley’s special international role in public service — that he was promised as compensation for not being sent to Brussels as the UK’s EU commissioner — is agreed, South Cambridgeshire could be another distant safe seat, with 7,838 votes over the next largest party.

But whichever constituency Boris plumps for, and however compatible for him to continue to serve as Mayor, he will still be breaking a clear promise that he made during his mayoral campaign: ‘I made a solemn vow to Londoners to lead them out of recession, bring down crime and deliver the growth, investment and jobs that this city so desperately needs. Keeping that promise cannot be combined with any other political capacity.’

Boris wants to be Tory leader, and to become Tory leader he needs to give a number of his more sceptical parliamentary colleagues the impression that they can trust him. Explaining how he hasn’t broken that campaign promise will be far trickier than choosing which seat to stand in — and could be far more important in deciding whether he really gets a shot at the top job.

Tags: Boris Johnson, Conservatives, UK politics