Ministers insist it is a worst-case scenario. But with no new deal in sight, the dangers set out in a document they wanted to hide must be taken seriously

Even for a government that prides itself on high-handedness, Jacob Rees-Mogg’s vicious attack on consultant neurologist David Nicholl was a low point. Dr Nicholl, who drew up a risk register for the newly released Yellowhammer no-deal Brexit planning document, asked Mr Rees-Mogg, on live radio, what “level of mortality” he would regard as an acceptable price for leaving the European Union with no arrangements in place. Since this was a direct challenge to ministers’ strategy of trying to normalise what should be unthinkable, Mr Rees-Mogg’s anger was not surprising. His insolence, however, in comparing Dr Nicholl to the struck-off anti-vaccination campaigner Andrew Wakefield, proved too much for his frontbench colleagues and Mr Rees-Mogg was forced to apologise.

Now that Yellowhammer has been published, it is clear why Dr Nicholl felt compelled to confront him. No-deal Brexit is a recipe for chaos, with medical supply shortages near the top of a list of consequences that are already scaring people around the country. While the long-term impact of a bitter divorce is strategically more damaging than any initial shocks, even voters tempted to buy into Mr Johnson’s no-deal bluster could be put off by the prospect of two-day traffic jams, energy price rises, civil unrest or a lack of clean water.

For Gibraltar and Northern Ireland the prospects are far bleaker, with a revived black market described as “likely”, particularly in border areas where criminals and terrorists are already active. Even given all the politics that surround Brexit, it is extraordinary that ministers thought it appropriate to hide such warnings from parliament and the public.

Both tips of the government’s two-pronged damage limitation exercise – that Yellowhammer represents a worst-case scenario, and that a deal is in any case on the cards – require careful handling. Since other versions of the Yellowhammer document are headed “base case”, it seems more likely that it sets out what civil servants believe will happen rather than what they think won’t (even if further attempts at mitigation are now in train), while the latest claims about a new deal being within view are at odds with the resignation statements of Amber Rudd and Jo Johnson.

Angela Merkel’s warning of the risk to the EU that could be posed by a low-tax, low-regulation “Singapore-on-Thames” on its doorstep is more illuminating. That such threats are being taken seriously, following Brexit negotiator David Frost’s announcement that Mr Johnson’s government wants to walk back from Theresa May’s commitment to a level playing field on social and environmental standards, should alarm everyone who wants the UK to continue in a constructive partnership with our neighbours, whether within or outside the EU. Given the enormous difficulties that would beset trade negotiations were the UK to pursue such a course, it is tempting to dismiss such statements as empty boasts, intended to force the EU’s hand with regard to Ireland. But Yellowhammer provides some support for this week’s complaint by a French foreign minister that the UK is attempting to negotiate “side deals” with individual member states, and subvert the Brussels process.

Since parliament has all but ruled out no deal, Yellowhammer’s predictions are not as frightening as they might be, even if an extension from the EU is not guaranteed. But it remains extremely disturbing that members of the prime minister’s immediate circle apparently believed, as recently as last weekend, that riots and shortages could be features of the near-future for which he is readying the country.