‘Steve Baker often disagreed with me, sometimes very strongly, but he was a rare person in the campaign – an honest man.’ That was the verdict Dominic Cummings passed on High Wycombe’s MP in a post-referendum wash-up blogpost on why and how Vote Leave did what it did.

Those are relatively rare words of genuine praise from Boris Johnson’s new senior adviser. If you’ve read Cummings’ blog, and if you haven’t then you should, you will already know that he pulls approximately zero punches on basically anything or anyone, especially when assessing people on his own side. ‘Many hours of life I’m never getting back were spent dealing with abysmal infighting among dysfunctional egomaniacs…’ is just one sample discussion of some of his enforced allies in the same article.

So there’s every reason to believe him when he has something positive to say about Baker. As well as recognising his deeply-ingrained honesty, he ascribes to him ‘a vital role’ in the failure of the attempt by some MPs and Vote Leave Board members to turf Cummings out of his role as Vote Leave’s strategist and campaign director.

The two had various wobbles and fallings-out during the campaign itself, as Cummings conceded within that compliment – being honest but wrong about things is preferable to being a liar and wrong, but still not as good as honest and right. But Baker’s intervention during that coup helped to avoid otherwise certain disaster for the whole campaign, and his work in Parliament keeping the pressure up on the Government over the terms of the referendum helped to move the dial subtly but beneficially in Leave’s favour.

Baker’s honesty can inspire those around him, infuriate them, or discomfort them – neither really matters to him more than that he is sticking with what he believes to be true. In that, he’s rather like Cummings himself, whose life’s work is focused not so much on politics as on a battle to assert the primacy of evidence and reason over what he sees as the dominance of self-serving delusion, routinely excused after the fact by a confection of self-fulfilling deceit. Both men hold to that insistence on clarity despite – or sometimes because of – the degree to which others in Westminster find it uncomfortable.

It’s a defining and dividing quality, particularly in politics. It’s what has made Baker a raven in the Tower for some Brexiteers, treated as their sure indicator of when all’s well or when something’s wrong, and simultaneously a figure of fury for others who believe his “Brexit hard man” stance over the Withdrawal Agreement might cost Brexit entirely.

Cummings and other Vote Leave veterans – and therefore the Government – know the benefit of having him on-side rather than in rebellion. Vote Leave benefited from Baker acting as a rebel against Cameron over purdah, for example, and the strategist himself benefited from Baker’s rejection of rebellion during the internal coup attempt.

But this time, they’ve lost him, at least from what Corbynites would call Core Group Loyal. While Baker was often seen in lock-step with Boris Johnson and his coterie during the leadership campaign, last night he walked out of Downing Street without a job, having turned down an offer to be restored to his old job at DEXEU.

His tweeted announcement of that decision said that “I cannot repeat my experience of powerlessness as a junior DEXEU minister”, but also that “I have total confidence in Boris Johnson to take us out of the EU by 31 Oct.”

It’s a slightly confusing comment: the experience of powerlessness in DEXEU as the Cabinet Office secretly prepared Chequers surely wouldn’t be repeated by a Prime Minister in whom you have total confidence to keep their promise. It appears to be a case of once bitten, twice shy – a junior DEXEU post doesn’t have the guaranteed access or power to absolutely certainly prevent a repeat of the last bitter experience.

More important than the question of what just happened, though, is the question of what happens next.

Baker is not in the tent as a Minister, but that does not automatically make him a rebel or an enemy. He is currently Deputy Chairman of the ERG, and might well step up to become its Chairman – but the Government has divided the ERG by bringing some of them into office, not least Jacob Rees-Mogg as Leader of the House. The interesting question is whether Baker will establish himself as de facto leader of the remainder, the ‘Spartans’ willing to make a stand at all costs, and what influence he might have on them if so.

Some of them are the very same MPs who were in direct conflict with Cummings in the Vote Leave days, and whom the strategist has since derided as ‘the narcissist-delusional subset of the ERG… too busy shooting or skiing or chasing girls to do any actual work. [They] should be treated like a metastasising tumour and excised from the UK body politic.’ That’s often quoted as being his verdict on the whole ERG, but it is not – the “subset” is a specific portion.

Back then, Baker, the rare honest man, looked past the personal enmities, recognised the necessity of what Cummings was doing, put the mission first, and thereby helped win the day. A great deal could now rest on him doing the same again.