However, while it may be too early to crown the key contenders, camps are inevitably forming. Therese Coffey, the Work and Pensions Secretary, is said to be supportive of her cabinet colleague Liz Truss, the Foreign Secretary, as a potential successor.

As one former cabinet minister explained: “Hunt will go back into any race, along with Truss and Rishi. I suspect Priti will also want to throw in her hat along with Sajid and Gove. Mark Harper will also probably run and possibly even Hancock.”

Harper, a former chief whip and the leader of the Covid Recovery Group of Tory backbenchers, has denied he is co-ordinating letters of no confidence. Nadim Zahawi, the Education Secretary, has also been touted although one insider described any bid as “a bit of an overreach.”

One Truss ally suggested it would be better for her leadership hopes if Mr Johnson “hung on for a bit”, adding: “She’s very popular with the ConHome faithful but she needs a bit more time to convince the party and membership that the country would consider electing her in 2024.”

In voting for Brexit, Mr Sunak would arguably have one over remainer Ms Truss in Red Wall seats but both will be competing from the same ideological base.

As one source who has worked closely with both ministers put it: “They are both unashamed Thatcherites.”