What Johnson likes about her is that she reflects parts of his personality – she is an optimist. 

But it’s also why her supporters believe her success is tied up in his. “Boris Johnson needs to go out on a high for Liz to succeed in a leadership contest. If he leaves on a low, MPs will want to replace him with the opposite,’ says one Ms Truss ally.

But among MPs and supporters, she has already developed a power base should the moment come. A regular on the think tank circuit, she is viewed as a true blue – speaking against tax rises around the cabinet table. She has also been working the circuit – wooing MPs at 5 Hertford Street and touring local associations. She was a guest of honour at Jackie Doyle-Price’s Christmas Abba-themed karaoke night.

Red Wall MPs were reported to have set up a Liz for Leader WhatsApp group – which was hastily shut down when word spread. She certainly has a loyal following among the younger intake. As Dehenna Davison, the MP for Bishop Auckland, told me: “[The] thing that I admire the most is the fact that her outlook is so positive and optimistic. She’s a free marketeer. 

“She really is a freedom lover and that is so important; freedom is so central to what we Brits believe in.”

She has also gained admirers for sticking it out in a man’s world where her male rivals are often praised as big thinkers and Ms Truss lightweight. One of her favourite Taylor Swift songs is The Man, with the lyric: “I’m so sick of running as fast as I can, wondering if I’d get there quicker if I was a man.”

She previously told me: “As a woman in politics you do face a particular criticism sometimes and there is this myth aboard and I blame The Thick of It with the sort of Nicola Murray-type minister the sort of sensible woman who is a bit clueless.”

She still has plenty of critics. There are plenty of old hands who roll their eyes at her social media and argue she is insufficiently serious for the Foreign Office let alone No 10. These MPs are more likely to favour Mr Sunak. 

The race between the two is already hotting up – with Ms Truss appointing her own “instagram guru” to go up against Sunak’s social media.

But the key thing that will decide Ms Truss’s future is not an Instagram post but her new brief. As George Osborne, the former Chancellor, noted: “The capable Liz Truss now has the tools to be the most powerful Foreign Secretary for many decades – foreign policy, trade with our most important markets and aid policy all in her brief for the first time.” If Ms Truss can do that, she will soon become the bookies’ favourite to succeed Boris Johnson.

Katy Balls is deputy political editor of The Spectator