What does Rory Stewart’s time at the helm as prisons minister tell us about his fitness to lead the Conservative party and our country? In January last year, I wrote an open letter to his boss, Justice Secretary David Gauke with some thoughts on how to deal with Britain’s shameful prisons crisis.

In it, I referred to Gauke’s new prisons minister, who, ‘given his diplomatic experience in conflict zones, will know a bullshitter when he sees one, which can only be good news when he meets the people who are running the wreckage of our probation system.’

I was right about Stewart’s low tolerance for bureaucratic abstractions and managerial verbiage. The unfolding months saw a calm, determined but very focused coup that deposed dissembling mandarins and ensured direct ministerial control in an effort to try to restore order and control on prison landings. The ‘hands off’ ministerial conventions that sustained mediocrity and underperformance in our criminal justice system were ditched in place of polite but relentless questioning.

Why were prisons disgracefully filthy? Why were all the windows broken? Why did those in charge of delivery spend so much time behind their desks playing with process when they should have been out on the ground saying, ‘this is disgusting, sort it out’?

I got to know Rory Stewart quite well in the intervening period. I had worked for Michael Gove leading a review of Islamist extremism in prisons in 2017 and saw some interesting similarities.

Both are disarmingly polite. Both actually engage, ask the right questions and listen. Each has a formidable intellect and in my direct experience neither hesitated to act when the evidence required it. In Stewart, unmolested by the fratricide of the previous leadership contest, there was also – and remains – a keen sense of national service above all else. In conversation, you detect a rare and attractive seriousness of purpose which has not elided into crippling self-regard and is built on authentic foundations. A man who walked across Afghanistan in 2002 surviving on his wits is on paper more than a match for his rivals for the Tory throne who were then mostly wetting their feet in the think tanks of SW1.

I don’t think Stewart can need politics as much as it needs him right now. He’s often been described as a man with a hinterland – someone whose outside interests and eclectic achievements meant he could easily melt away into a less arduous game if politics played him a dud hand.

In fact he came up aces when defence secretary Gavin Williamson finally blew himself up. Stewart was rewarded for his energetic fealty to Theresa May’s doomed withdrawal agreement by a reshuffled seat in the cabinet at DfID. In ordinary times, this dream job for a man devoted to the world's liminal places would have held him for a few years at least. But times are far from ordinary and Theresa May’s field promotion in the dying days of her premiership has projected Rory Stewart from one of John Buchan’s more unlikely creations into a serious leadership contender.

Back to the prisons brief. Stewart is widely acknowledged even by his critics as someone who was passionately intent on getting things done in a ministerial boot camp many of his predecessors were just grateful to emerge from unscathed. He was genuinely interested in the operational detail. He made sure that his perspective on the front line of prison reality and reform was not mediated solely by corporate suits or the usual pressure groups. He very quickly discerned that the critical issues were simple – drugs, violence and decency – and bet his career on fixing them by announcing he’d resign if violence in ten of the most blighted prisons was not reduced in a year.

His critics have made much of the fact that he managed to evade accountability on this pledge through his recent promotion to cabinet. Moreover, although there were encouraging signs of a slight reduction in truly awful rates of violence, it is far from certain that they would have genuinely changed enough to save him.

The implication, that he would somehow have spun himself out of making good on his promise speaks volumes about our current trust in politicians and misrepresents him.

I think, having dared to try and having failed, he would have walked. In this regard he is different from the herd of other contenders. He was the most morally and intellectually engaged ‘minister for Sisyphus’ in many a year. He relished difficult office in an authentic crisis and took hold of the agenda persuading the most cynical of audiences he was for real. That persuasive moral acuity will be essential to any leader hoping to bring party and country together. It could also be a game changer in Brussels. They aren’t terribly used to polymaths on the other side of the negotiating table. Or people who once ran a province in Iraq. It might be enough.

120,000 conservative members like me will soon turn their lonely eyes to the candidates emerging from the first stage of our leadership contest. Some of these candidates apparently believe that in order to save the Conservative party it will be necessary to destroy it. Others won’t even need that excuse. A poor choice might well herald five years of Venezuela lite. The stakes could not be higher. Rory Stewart is a paradox – he lacks the dubious star quality of many of the big beasts parading through the studios, yet has life experience and achievements they could only dream of. I’ve seen it – he’s a good man in a tight spot. He’ll get my vote.