What Tory MPs actually talked about at conference wasn't Brexit – it was May's possible successor. And there were some surprises

While most potential runners openly paraded their wares at the conference, one dark horse played it more subtly. They say it’s the quiet ones you have to watch

Forget Abba, and remember The Clash. “Should she stay or should she go?” – how long Theresa May should remain in Downing Street – was what ministers, MPs and Conservative activists really discussed in the margins of their party conference, rather than the fine print of a Brexit deal.

Although May’s well-received speech has bought her some time, we can’t entirely rule out an attempt by hardline Brexiteers to oust her in the coming weeks when the penny drops about her “Chequers 2” plan to keep the UK in a form of customs union. After running his union flag up the pole (again) in Birmingham, Boris Johnson might decide that he can’t be afraid to strike (again). However, the likelihood is that her party will give her the chance to get Brexit “over the line” next March.

The main question in Tory minds is whether May should stay or go soon after next March. The subtext of her conference speech was that, having walked through the Brexit fire, she would have earned the right to implement a domestic policy agenda. Indeed, May allies are again talking up the prospect of her leading her party into a 2022 election. Probably their real goal is to secure May a few more years in Number 10; they know that last year’s disastrous election campaign will not be forgotten.

Some cabinet ministers want May to stay on to “finish the dirty job” of negotiating a trade deal with the EU and “take the bullets” from Tory MPs. One told me: “A leadership contest next spring would be dominated by Brexit, and whether a candidates was a Leaver or Remainer. We need time for the wounds to heal. Then we could choose the best leader to beat Labour in a 2022 election.” These ministers point out that there is still no obvious successor who could unify a deeply divided party. One option would be to allow May to stay on the understanding she would announce at next year’s party conference that it would be her last as leader.

Surprise, surprise, such arguments are put forward by potential candidates who backed Remain in 2016. They know that Tory members – who make the final choice after the runners are whittled down to two names by the party’s MPs – are more likely to choose a Leaver than a 2016 Remainer even if, like Sajid Javid and Jeremy Hunt, they are now born-again Leavers. So better to let the dust settle.

Conversely, Eurosceptics seem more inclined to favour an early leadership contest. If the UK and EU agree only a vague political declaration about their future relationship, which is likely, an incoming leader could still shape it. A trade deal could take years, and might drag on until 2022; May would have to be deposed to stop her fighting another election.

So a Tory contest next summer would suit Brexiteer potential candidates such as Michael Gove, Dominic Raab and Andrea Leadsom. Would it come too late for Boris? Despite his rapturous reception in Birmingham, my impression there was that his star is on the wane.

“He has lost his shine,” one MP and former supporter said. “He’s 50 per cent of the guy he was as London mayor.” Although Boris could win a members’ ballot, he is struggling to win enough MPs’ support to make the shortlist. His best hope is turmoil over a deal this autumn.

While most potential runners openly paraded their wares at the conference, one dark horse played it more subtly – Penny Mordaunt, the international development secretary and 2016 Leave campaigner. They say it’s the quiet ones you have to watch. Keep an eye out for her.

The field could be very big. Up to 12 candidates could run —some, such as Gavin Williamson, Liz Truss or backbencher Tom Tugendhat, in the hope of winning promotion rather than the main prize.

Despite Ruth Davidson’s announcement that she will not seek to become prime minister, some of her many Tory admirers have not given up hope she might change her mind after the Scottish parliament elections in 2021. Indeed, I hear whispers that May has a woman successor in mind. Who else other than the brilliant Davidson, who would scare the pants off Labour? Perhaps May has a cunning plan to hang on until Davidson takes the reins for a 2022 election.

If she delivers Brexit, May would get a bounce in her party. But I doubt it would last very long. To ensure a dignified exit and avoid being pushed out, she might have to announce next spring that she will depart within months. Although she would like her thank-you present from her party to be letting her carry on, it might well tell her: “Thanks, but no thanks.”