Wanted: someone to advise King Herod on care of firstborns. Sorry, that should, of course, be “Boris Johnson on ethics”. The successful applicant must be impervious to embarrassment, willing to work all hours just to keep track of all the allegations, and even then probably resigned to following the two previous independent advisers on ministerial interests out of the door in due course. Assuming Carrie Johnson couldn’t be tempted, it’s hard to imagine where Downing Street hopes to find a new keeper for the prime minister’s conscience, after Christopher Geidt became the second handpicked moral arbiter to resign – this time in alarmingly mysterious circumstances. In a letter finally winkled out of a reluctant Downing Street today, Lord Geidt said he had quit after being put in an “impossible and odious position” over government proposals that risked a “deliberate and purposeful breach of the ministerial code”, without elaborating. Whatever fresh hell this signifies – Johnson’s response suggests something to do with protecting the British steel industry from an influx of Chinese steel, which is a sensitive issue in some “red wall” seats; but, as ever with the prime minister, it feels like only half the story – Geidt clearly saw it as opening the door to more widespread flouting of the code. “Is there any point appointing a new ethics adviser for a prime minister with no ethics?” asked the SNP’s Carol Monaghan, during an oddly frustrating parliamentary debate over a resignation letter nobody had at that point been able to read. Interestingly, the paymaster general, Michael Ellis, neatly ducked a question about whether the advisory role would simply now be ditched. Geidt had “demonstrated diligence and thoughtfulness” in his role, he said, which under any other administration would be praise, but under this one makes you wonder how he lasted so long. There is a genuinely thuggish edge developing to this government, with its arrogant refusal to accept scrutiny of its increasingly out-of-control behaviour. The European court of human rights inconveniently puts the brakes on your preposterous plan to ship asylum seekers off to Rwanda? Then threaten to pull out of the convention altogether, just like Vladimir Putin’s Russia. The archbishop of Canterbury dares to judge your treatment of refugees ungodly? Threaten to kick bishops out of the House of Lords, where generations of Lords Spiritual have sat since the 14th century – the kind of tradition Conservatives used to be keen on conserving. Britain is, of course, still a functioning democracy, and the resignation of one exasperated official (or more accurately two, in quick succession) doesn’t in itself change that. But we would know exactly what to call this sort of thing if it were happening under Donald Trump, or Brazil’s Jair Bolsonaro, or the far-off leader of some corrupt and institutionally fragile state. The niggling, unexplained question here, meanwhile, is why Geidt had to be consulted on what sounds like a question of trade law, something more obviously directed at the attorney general or experts at the Department for International Trade. Did some senior civil servant cry foul? Could there be some other conflict of interest lurking in the background? There is an odd mismatch between the emotional strength of Geidt’s criticisms and the idea that this was all down to some arcane-sounding dispute with the World Trade Organization. Whatever he was asked to approve was, he felt, “an affront”; letting it pass would “license the suspension of (the code’s) provisions in governing the conduct” of other ministers too, opening the floodgates. When a former royal courtier as silky as Geidt – who only a week ago told MPs he avoided advising Johnson on his personal obligations under the ministerial code because if Johnson ignored him, “we would find ourselves in a position where self-evidently the confidence would have been lost between the prime minister and the adviser” – snaps, something is up. You have to pinch yourself to remember that less than a fortnight ago Johnson was pleading for his political life in a no-confidence vote that for many would have been a chastening experience. What worries me is the prospect of a cornered prime minister, far from cleaning up his act, concluding instead that he has nothing left to lose. Gaby Hinsliff is a Guardian columnist