The British government has published its plans for a post-Brexit ‘points based’ immigration system. The idea is to establish rules for immigrant workers from the EU in line with those that apply currently to workers from elsewhere in the world. The ‘points’ will be awarded on a variety of measures – can you speak English? do you have a PhD in a STEM subject? are you in a ‘shortage occupation’? – and a good performance on one criterion will offset a shortfall on another. People the government judges to be ‘high skilled’ will be (comparatively) welcome; those whom it considers ‘low skilled’ will not be welcome at all.

The government’s focus, at least officially, is almost entirely economic. Migrants are welcome insofar as they benefit ‘us’. These human beings, some of whom are already sitting as ‘stock’ in our national store cupboard like tins of tuna for a rainy day, are there to boost production at UK plc. The new policy contains some pro forma references to the ills of exploitation, but imposes vulnerabilities on a whole new group of people who are currently able to walk away from a boss who skims their wages, extracts unpaid overtime, touches them up or worse. The message: you are here to do a job, a particular kind of job in a particular industry, and if you lose it then home you go; even if home, for all emotional and practical purposes, is here. Faced with such options, many will do what it takes to stay, and their managers will know that they will.

There will no longer be a route to permanent settlement for ‘low skilled’ workers, with ‘low skilled’ here meaning poorly paid rather than lacking in dexterity, inventiveness, imagination or empathy. The industries that used to rely on large numbers of migrants from Eastern Europe – social care, construction, hospitality and agriculture – will no longer be able to. What will happen? The government claims that the shock will be mitigated by the existing ‘stock’ of EU migrants and by workers on seasonal visas, perhaps supplemented by the dependents of the ‘high skilled’ migrants it plans to make continued use of, though it is doubtful whether the partners of Italian engineers in London and the South-East will be up for picking broccoli in Lincolnshire. The currently envisaged number of seasonal agricultural workers is quite low. So that leaves three options consistent with the government sticking to its line: businesses fold, ‘technology’ replaces labour, or Brits do the work.

It certainly seems likely that some businesses will go under. Still, people have to be fed, houses have to be built and the bottoms of the elderly have to be wiped. If less food is produced in the UK, and imports from the EU become costlier and scarcer too, then that leaves supply from elsewhere: chlorinated chicken, perhaps. But where will the fruit and veg come from?

Robots and other technological solutions are no doubt part of the future imagined by Downing Street advisers – and the UK could do with a productivity boost. Perhaps some businesses will be able to make the necessary investment quickly enough. But most won’t. And the technology to replace most vegetable-picking and all bottom-wiping has as much chance of being quickly invented as technological solutions to the Irish border problem.

So that leaves us with the Brits. Priti Patel has suggested that 20 per cent of the working age population are inactive, but most of them can’t or won’t pick the vegetables. Some are wiping bottoms already, but they can’t both be a Conservative substitute for social care by looking after their own family members, and at the same time be the people to save the social care sector by doing the job for cash.

There are no short-term solutions. Longer-term, though, there may be one. If the UK is going to buy its ‘high skilled’ workers from overseas, it will choose to produce its ‘low skilled’ ones domestically. Instead of ‘education, education, education’, Britain will have to generate large numbers of young people without the skills, prospects or aspirations that education brings. Maybe that’s a winner for the Tories, since education reduces the propensity of people to vote for them. For young Britons from poorer backgrounds, squeezed out of university places, gathering turnips may be the bitterest Brexit harvest yet.