Just when you thought it couldn’t get any worse.. Boris is back

His wife, Marina Wheeler, had thrown him out after – according to friends – ‘one affair too many’, and he had caused widespread offence by comparing Muslim women who wear burkas to ‘letterboxes’, prompting some Tory MPs to vow that they would leave the party if he ever became leader.

Put together, it was the Boris brand distilled into a particularly nasty brew, and one which caused his one-time admirers among the Conservative grassroots to think again about whether they wanted him as their next leader.

Not only that, he had quit the cabinet as foreign secretary over Theresa May’s Brexit deal, but subsequently failed to come up with an alternative Brexiteer plan for leaving the EU. After years of positioning himself as a future leader and prime minister, it appeared that Johnson was being found out.

Six months on, and with a lot of water under the Brexit bridge, Johnson’s share price is gradually rising again. Having spent a lot of last year vying with other possible contenders like Jacob Rees-Mogg and Sajid Javid for votes in ConservativeHome’s monthly next Tory leader survey, the ex-foreign secretary is now the clear favourite, according to their latest poll.

Among the wider electorate, too, according to a rolling survey by YouGov, Johnson is the most popular Conservative politician, scoring a positive opinion rating of 32% (although 44% expressed a negative opinion). Seemingly unthinkable a few months ago, it is once again conceivable that he could lead the Conservatives into the next election, and even become prime minister within months.

This steady return of Johnson as the Tory grassroots favourite has focused minds in Downing Street and the cabinet. While most of their attention is on securing a workable Brexit deal, there are also signs of a Stop Boris campaign mobilising for some point after Brexit.

On Tuesday, the Sun reported that the prime minister has been hinting to cabinet ministers that she could step down this summer to lay the ground for a Conservative leadership contest that culminates at the party conference in October.

Setting out a protracted timetable would allow Johnson’s rivals to come forward and build up support to prevent him reaching Number 10. This strategy would echo that of Michael Howard, who, in the wake of losing the 2005 election, announced he was resigning as Tory leader six months in advance – opening up the field and ultimately letting relative newcomer David Cameron beat better-known rivals.

May has already announced she will not fight the 2022 election, and had been expected to stand down next year or in 2021.

Her own departure date will always be dictated to by the success or otherwise of UK’s departure from the EU – and if Brexit turns into a disaster, she could be forced from office well before 2021. After winning a confidence vote among Tory MPs in December, a second attempt to unseat her by her party cannot take place until next Christmas at least – but that does not prevent a rebellion in January 2020.

Prime ministers always want to choose the date they leave office, and if May could simply get Brexit ‘over the line’, goes the argument, it would make sense to go at some point this year, having achieved that one thing.

Without a clear rival for the Tory crown, a Johnson premiership isn’t as unlikely as it seemed six months ago. This matters because it would mean more than just a change of personnel in Downing Street, but Johnson pursuing a very different future free trade deal with the EU.

As a result, the future of the UK would be set on a very different path under a Boris Johnson government. A ‘blindfold’ Brexit, under which the future relationship is up for grabs even if a deal is agreed before March 29, would cause deep economic uncertainty for the UK and damage its trading prospects with the rest of the world. Whether there is a deal or not, Britain under Boris would move on to the hardest of ultimate Brexit outcomes.

Crucially, his one-time Brexiteer rival Rees-Mogg has fallen down the ranks of ConservativeHome’s monthly survey, and is now letting it be known that he has no ambition to lead the party. Instead, he is actively helping Johnson’s background leadership campaign by hosting ‘back Boris’ dinners at his five-storey, £6million mansion a stone’s throw from the Houses of Parliament.

Having been effectively the shop steward of backbench Brexiteers as chairman of the European Research Group, Rees-Mogg holds significant influence among Tory MPs, who will select the final two contenders in a leadership contest for a run-off among members.

There are a number of Conservative MPs from all wings of the party who would stand in the next contest, and among those tipped are environment secretary Michael Gove, who spiked Johnson’s leadership chances in 2016 by entering the race himself, and work and pensions secretary Amber Rudd, who is burnishing her centre-right credentials by adopting a – relatively speaking – more sensitive line on universal credit as well as keeping a pro-European flame burning in the cabinet for Tory Remainers.

Former Brexit secretary Dominic Raab has barely been able to hide his leadership ambitions, using a speech in a Brexit debate last month to set out his stall. Home secretary Sajid Javid, foreign secretary Jeremy Hunt and Penny Mordaunt at international development are also thought to be in the running.

Yet while they all have cabinet experience, none of them have the same levels of popularity among Tory members as Johnson. And if the Conservative Party is heading towards a split – which is within the realms of possibility if May pursues a softer Brexit compromise deal with Jeremy Corbyn – his prospects will rise still further.

Johnson has come a long way since writing two versions of his column on the eve of the 2016 referendum campaign, in favour of Remain and in favour of Leave.

He has apparently seized on figures showing increasing Conservative membership approval for a no-deal by doubling down on his support for that scenario, despite grave warnings from economists and businesses. But this week, the MP for Uxbridge and South Ruislip has also shifted his position slightly on the Northern Ireland backstop by suggesting he could weigh in behind May’s deal if she negotiated a time limit with Brussels.

This shift is significant because he had previously opposed the backstop outright. There are signs this week that other Brexiteers in the ERG are also softening their approach towards May and the backstop – to try to head off the prime minister entering a soft Brexit deal with the Labour leader.

Tory Brexiteers are also mindful of Nigel Farage’s new Brexit Party, which could threaten to snatch Conservative votes at the next election in the same way UKIP did during the last decade. They need to shore up the support of Conservative Leave voters across the country by holding the Brexit line. This makes it more likely than not that the next Tory leader will be a Brexiteer.

Yet one group of Tories who would be dismayed at a Johnson leadership are Ruth Davidson’s Scottish Conservatives. Last year they launched their own ‘stop Boris’ campaign, dubbed ‘Operation Arse’, and last weekend the Scotsman reported that those behind it have declared it a success.

Davidson’s Conservatives should be taken seriously by the Tory leadership – not least because the 2017 election saw a surge in Conservative votes in Scotland, with 13 MPs elected, one of the only successes for May on the night.

But it is clearly too soon to declare victory for Operation Arse, given Johnson’s resurgence. Of course, a more comprehensive way for the prime minister to stop Boris would be to call another snap election – and this time win it outright. As fanciful as this notion seems, the Times published a poll this week by YouGov, using the same methodology that correctly predicted the 2017 hung parliament, which now points to a narrow victory for the Tories.

We have been here before, when May had been tempted by the polls into trashing her own cautious brand in favour of an election. But if the Brexit deadlock continues, it could be an option gaining traction in Number 10. What is more likely is prime minister Boris Johnson on the steps of Downing Street before Christmas.