While Westminster has been fixated on Theresa May’s battle with Brussels over her Brexit a deal, a battle already being billed as the dirtiest of a generation is playing out away from public view in Parliament.
At stake is the future of both Britain’s future outside of the European Union – and the Conservative Party as a major electoral force.
Up to a dozen senior Tory MPs are actively mulling whether to mount leadership campaigns, to replace Mrs May when she quits – as expected – later this year.
One MP says: “Everybody is trying to gauge what support they have got.” Another MP says: “It is early days – this is a slippery electorate… It is not as though there is a runaway favourite.”
And given the wide open nature of the field, it is hardly a surprise the teams are drawing up “war books” about one another according to one adviser, shining a light on controversial historic articles, details of alleged sexual peccadilloes and unsavoury claims about their partners.
One adviser said that “without a doubt” the campaigning in the upcoming Tory leadership campaign will be the dirtiest for decades. “The biggest feature in Westminster is people looking for dirt on other people
“They are all at it [war books]. Everyone is going on about the war books, who has got what. It is already quite a nasty campaign.
“The main focus at the minute is how you can take people down – it is not a battle of ideas yet. It is people trying to knee cap each other.”
The battle for votes in the tearooms and corridors is already fully underway. While none of the leadership teams will confirm numbers Jeremy Hunt, the foreign secretary, is seen in the “unenviable position” of being the early front runner with one observer saying he has pledges of between 70 and 80 Tory MPs.
Both Sajid Javid, the Home Secretary, and Dominic Raab, the former Brexit secretary, are said to have won the unofficial backing of 40 MPs.
Further behind is Boris Johnson, the former foreign secretary, who is sitting on a “core support of 25 MPs without having to work” rising to – according to his cheerleaders – as many as 70 MPs, including Jacob Rees-Mogg, the ERG chairman.
Each is tailoring his or her offering to MPs who have to whittle the field down to just two candidates to go in front of the membership.
Mr Hunt – who is in Japan this weekend on official business when he will demonstrate his linguistic skills by teaching English to Japanese students – is emphasising a “compassionate Conservatism”, saying the Tories must show they are not just a “money, money, money party” but have a “social mission” as well.
But his rivals are already describing him as the “establishment candidate” who is likely to pick up the support of Number 10. Plenty of observers say this could damage his chances among MPs furious about the Brexit talks.
Mr Javid, an arch-Thatcherite, has been trying to convince MPs to back him by emphasising his social justice credentials, built around the importance of the family at a dinner held by the Social Justice Coalition in the Commons last Monday, coupled with his experience of four big Cabinet jobs.
Mr Hunt and Mr Johnson have both reportedly addressed the same dinner some weeks earlier. One friend of Mr Javid said the Home Secretary had “aced it and Jeremy Hunt was uninspiring”.
MPs who back Mr Raab, whose anti-EU credentials cannot be questioned, stress his support for the core Tory values of helping others to get on through determination and hard-work, while building a fairer society.
Meanwhile, Mr Johnson’s team are hanging his appeal on his popularity outside of the M25 – pointing out how former Labour leader Tony Blair said a fortnight ago that he was the Tory politician who could beat Jeremy Corbyn.
One supporting MP said: “He can deliver us Brexit and a victory. Boris is that person. He is the sort of person you can turn to in a crisis. When we get him to the members, he is going to win.”
Other outsiders in the leadership race are more forthcoming in their policy plans, perhaps in a bid to attract attention.
Last week Matt Hancock, the rising star Health Secretary, raised eyebrows by calling for a return to modern-day patriotism with an appeal to Tories “to sound like we actually like living in this country”.
That came after Liz Truss, the Chief Secretary to the Treasury, last weekend called for party members to be given votes on policy motions at the annual party conference, while also questioning the spiralling costs of the HS2 scheme
The large number of possible candidates – Michael Gove, the Environment secretary, is considering running, while James Cleverly and former chief whip Mark Harper are mulling standing – means talk soon turns to a Tory version of the online dating app Tinder where MPs have to swipe Left or swipe Right to find their ideal running mate.
Mr Johnson is already understood to be eyeing up an alliance with Amber Rudd, the Work and Pensions secretary, who can bring with her other Remain-supporting MPs. Donors are said to be keen on the union of the two socially-liberal Conservatives.
However sources close to Ms Rudd made clear she has not decided who to back, but she will not back any candidate who has considered leaving the EU without a deal to be “a viable option” – and may conceivably run herself.
Ms Rudd has formed the “One Nation” group of MPs within the Tory party in part to ensure MPs could back a leader who will develop “a plan for domestic issues” to take the party beyond Brexit.
Mr Hunt is rumoured to have offered the position of foreign secretary to either Penny Mordaunt, the International Development secretary, or Tom Tugendhat, the chairman of the Foreign Affairs committee.
A source close to Mr Hunt denied he had offered jobs to leadership rivals. The source said: “He hasn’t offered any jobs to anyone, and it’s not his style to stoop to this kind of briefing against colleagues.” He added that Mr Hunt had been well received at the social justice dinner.
All the frontrunners are lining up advisers. Mr Javid has signed up Matthew Elliott, the former chief executive of Vote Leave, while former Tory MP James Wharton is backing Mr Johnson.
Mr Raab is being supported by Paul Stephenson, another well-respected former Vote Leave executive, while Mr Gove, who has still not been forgiven by many Brexiteers for pulling out of Mr Johnson’s leadership campaign in 2016, is being advised by Henry Newman, a former aide who runs the Open Europe thinktank.
Mel Stride, a Treasury minister who is backing Mr Gove, has shown MPs pie charts purporting to show that he would have broad support across the country. One MP claimed Mr Stride had said the data showed that Mr Gove was the only candidate who could beat Mr Johnson.
Part of the problem is that Mrs May has only committed to leaving once the Withdrawal Agreement is passed – which could happen anytime between now and at least October – making it hard for MPs to know when to start campaigning formally.
One adviser says: “It is a phoney war at the moment – no one knows when it is going to start or how long it is going to be.
“So everyone is unsure about the pace of when to attack things. It is like being in a horse rate and not knowing where the finishing line is or when the start is.”
What is clear is that the Tory party cannot choose a leader who cannot win an election against an Opposition leader like Jeremy Corbyn.
One Brexit-supporting Conservative MP says: “This is existential. Getting this next choice right is absolutely fundamental to our chances of forming the next Government. More importantly it is very likely to be fundamental to our chances of delivering Brexit.”