I’m not sure how many winnable Tory seats still need a candidate, but the Prime Minister has invited the Mayor of London to get in the ring. Here’s what he said in an interview with James Corden, who was guest editing The Sun for Sport Relief:

Screen Shot 2014-03-21 at 07.54.15Corden: If you are in a room together, like even if you are at the Olympic stadium and he [Boris] is sat the other side of the stadium…

Cameron: …he still makes me laugh…

Corden: …and you are sat the other side can you feel his eyes piercing at you going… Ghaaaaaaar – I want your job!?!

Cameron: That is brilliant. No. It wouldn’t be a great job to have if people didn’t want it. There is nothing ignoble about wanting my job. But I thought he did brilliantly over the Olympics. He helped create that sense that this was a great time for Britain.

Corden: That is what I mean. Is that not annoying.

Cameron: No.

Corden: Really?

Cameron: Definitely honestly no. I promise you, honestly no.

Corden: So am I right in thinking he has to run in the next election?

Cameron: That is what I think he should do. I want to get him back in Parliament, I think he is a great. It a bit like football as we said earlier, if you have got a great striker you want him on the pitch. It is up to him. He can complete as Mayor, or he can stay on as Mayor and come back to the House. I want him on the team.

Interestingly, Cameron talks as if it’s a given that Boris is out for his job. ‘It wouldn’t be a great job to have if people didn’t want it. There is nothing ignoble about wanting my job,’ he said. Quite so.

But that’s not the same thing as having him on the team. There’s no reason why Boris could not be made Tory chairman, for example, to rally the troops and co-ordinate the campaign. He doesn’t need a seat. But he has yet to say whether he wants one.

In asking Boris to show his hand now, Cameron may argue that he’s reducing the will-he won’t-he speculation that surrounds the Mayor. This matters because, for reasons that only a psychologist could understand, senior Tories are much taken by leadership speculation at the moment – which is depressing, as it suggests even they think they’re about to lose.

The conspiracy theories (and there are a great many around) argue that if Cameron wins in 2015 then Osborne, his co-pilot, is a shoo-in for the job should the PM stand down in 2018. The most likely scenario which has Boris as leader involves Cameron losing next year’s election. So (the theorists continue) it suits Boris to stand back from a coalition car crash, then emerge as the untainted champion of true Conservatism while his main rival, Osborne, would be see as co-architect of failure.

By having Boris stand in 2015, and play a major role in the election campaign, Boris could not then distance himself from it. So the best way of reducing Boris’s chances of leader later is to rope him in now.  And if Boris does stand in 2015, it will not be seen as a hostile act but taking up his party leader’s invitation.

Or so the theory runs – it’s nonsense, in my view. Cameron played a key role in the 2005 campaign, only to emerge as a fresh face in the leadership race.

My take: Cameron, unlike those around him, is not thinking that far ahead. He just wants back in No.10. He knows Boris is a huge asset, who was elected Tory Mayor of a Labour city. He reaches part of the electorate that other candidates can’t. The more we see of him in the 2015 campaign, the better for the Tories. I imagine that Lynton Crosby, who was Boris’s strategist and now advises Cameron, agrees.

Boris may find it rather difficult to find a vacant seat now, as he’s not even on the candidates list, but one could probably be made vacant for him. Zac Goldsmith has hinted that he may hand over the not-entirely-safe seat of Richmond. So yes, there are plenty technical problems. But as Cameron knows, with Boris, anything is possible.

UPDATE: Here’s Boris’s response, in which he reserves his 2015 options:-

‘Having seen Miliband and Balls’ woeful response to Wednesday’s excellent budget it’s clearer than ever that a Labour government in 2015 will be an utter disaster for this country. Between now and May next year only two things matter to me – delivering for London and returning David Cameron to Number 10 as Prime Minister of a majority conservative government. I’ve got a huge job to do in London but I’ll be doing all I can to make that happen.’

Tags: Boris Johnson, David Cameron, General Election 2015, Tory wars