Imagine an arrangement whereby Ministers were specialists: the Health Secretary was a doctor, the Business Secretary a businessman, the Education Secretary a teacher, and so on.  At first glance, it looks like an improvement, since the Ministers concerned would know what they were talking about.  Second thoughts, however, bring doubts (or should do).

It is a fundamental of improvement that institutions need reform.  Look back 25 years or more, and you will see doctors opposed Ken Clarke’s NHS reforms, and teachers doing the same to Ken Baker’s education changes.  Glance at more recent history, and you will note Michael Gove getting the Baker treatment.  The danger of specialist Ministers is precisely that, unlike Clarke or Gove, they are not outsiders with a fresh eye.  Rather, they are in danger of being captured by the groupthink of their fellows.

Furthermore, specialism only takes one so far, anyway: for example, someone who has risen through the ranks of a big firm is likely to have a different take from someone else who started a business up himself.  And what does one do with the specialist Ministers after he has served for a few years in his specialist department?  The logic of the system suggests that he must be fired.  There is no Ministerial development.  Departments become a revolving door which one can enter only by the backbenches.

No, if Ministers aren’t delivering the reason, more often than not, is that clear direction from the top is absent.  Margaret Thatcher and David Cameron were unlike in many ways, but they had a feature of management style in common: namely, they appointed a fair share of effective Cabinet Ministers, and let them get on with it: Nigel Lawson, Michael Heseltine, Clarke, Baker, Gove, Theresa May, Iain Duncan Smith, Jeremy Hunt.  None of these were specialists in the departments to which those Prime Ministers sent them.

Which brings us to the case of Rory Stewart.  Unusually, even uniquely in modern politics, he is a figure from the world of John Buchan’s Thursday Club; a kind of latter-day Sandy Arbuthnot: diplomat, author, lecturer and traveller, who helped to run parts of Iraq post-invasion (he served in a compound besieged by Sadrists) and who walked across Afghanistan, where he introduced himself to Taliban fighters as a follower of the Prophet Jesus.  In the unlikely event of being entertained by whirling devishes in Istanbul, you will probably find that one of them is Stewart in disguise.

The Prime Minister’s January reshuffle went horribly awry, and Stewart’s move from the Foreign Office to the Justice Department, which was part of it, raised eyebrows.  Why move a foreign affairs and environmental expert to become Minister for Prisons?  Actually, Stewart may well turn out to be proof of the anti-specialist principle.  What makes a good Minister is hard grind, intelligence, cunning, a willingness to listen, an understanding of how to handle colleagues and the Commons and, above all perhaps, a well thought-through idea of what he wants to do.

Stewart definitely has clear ideas.  To his Secretary of State, David Gauke, falls the controversial business of planning for a bigger or smaller prison population, and justifying his choices to voters, or trying to.  Gauke’s predecessor-but-one, Michael Gove, had big ideas about how to improve prisons: drawing on his experience at schools, he wanted more autonomy for governors; league tables, and the takeover of failing prisons by successful ones.  Stewart’s room for manoeuvre is limited but his priorities are evident.

“My instinct is we need to get back to basics,” he told the Justice Select Committee in the wake of his appointment. “We need to absolutely insist that we are going to run clean, decent prisons. There have been too many very abstract conversations in the past two years about grand bits of prison policy.” He was speaking in the wake of a report on Liverpool prisons which found a disgusting jail full of rats, cockroaches, broken windows and piles of rubbish.  He told the committee that he wanted “more fixed broken windows and fewer drugs”.

There is undoubtedly more where Liverpool came from.  The unvarnished truth, whether one likes it or not, is that, for most voters, the old proverb applies: out of sight, out of mind.  Education and Health have strength in numbers: there is a mass of parents and patients to lobby for more funds.  Defence and, up to a point, policing can rely on public sympathy.  Prisoners have very little.  So it is today that we have news of what looks like another Liverpool – an emegency takeover at Birmingham jail.

Stewart is the choice of a certain type of fastidious Conservative to be the next Party leader.  He would be a kind of anti-Trump, which has its pluses.  We are all in favour of a Prime Minister who can quote Thomas Hardy in the chamber during a debate on hedgehogs, or cite Immanuel Kant and the categorical imperatice during a debate on mobile phones.  He has his following and is a feature of our Next Tory Leader survey.  But a questionmark hovers over whether he is too rarified for the highest office – though, on the other hand, this is (we are told) the age of authenticity.

One sign of his non-conventional status is his recent offer to resign if drug use and violence don’t fall within a year in ten prisons.  Either Stewart knows something we don’t.  Or the pledge is another instance of his unconventional approach.

Our insider take is that good Ministers avoid hypothetical questions about potential resignation – and that to do otherwise is, well, quixotic.  The voter in the street, by contrast, might well see Stewart’s words as a bracing demonstration of personal accountability.  What do you think?