Paper mountain, hidden Brexit: How'd you say immigration control would work?

Never gonna give EU up, never gonna let you down... er

Brexit: What if you haven't got five years' time served....

Assume for the moment that we can strike a deal covering all citizens who do qualify for automatic residence under EU law, and consider what we do about those who don't. We can possibly lob the ECHR in here to modulate our considerations. Say Chantalle from Cherbourg got a job Sheffield in February of this year. She had at that point a reasonable expectation that she could work in the UK for as long as she liked, so were the UK to deprive her of her leave to remain, might this not be infringing her Article 8 rights? Go in too hard and the Home Office will be up to the gills in EHCR cases, many of which it will lose.

So maybe Chantalle is OK, and maybe the other non-qualifiers are too. Consider the cut-off date.

The intent of the cut-off date is to avoid a rush of new EU immigrants anxious to get into the UK before Brexit. No such date has been announced, but proponents include Andrea Leadsom, who suggested it be the day after she became Tory leader just before her campaign fizzled.

Brexit minister David Davis says there might be a cut-off date but he can't announce it now in case this triggers a rush of migrants, while the Home Affairs Committee, suggests three (day after the referendum, day Article 50 is triggered, day of Brexit).

Skip over the fact that Brexit day is a cut-off date already, and consider the implications. You've already got that cut-off date baked-in because it's the day EU law ceases to apply (depending...), and then if you're applying EU law for permanent residency (which you are until that day), there's another baked-in cut-off date which is just under five years before that. So assuming Article 50 in Jan 2017, Brexit in Jan 2019, the other cut-off date was in Jan 2014.

By implication those proposing a cut-off date that's later than that (all of them) are effectively saying that they favour easier permanent residence terms than is currently the case. As they include the Brexit minister, this might be a signpost to the kind of "generous settlement" Theresa May envisages.

Davis floated a date in an interview with the Mail on Sunday immediately after his appointment. The Mail tastefully headlined its report We'll send EU migrant surge back, but that's what the UK would have to do if it fixed any date before Brexit day, and/or if it applied current permanent residence rules. The UK is currently subject to EU freedom of movement laws, so anybody arriving prior to Brexit can live and work here, and if the date were today, June 24th or whatever, anybody doing that would have to be chucked out on Brexit.

Processor overclock

Loop back to processing permanent residency applications here, because that's how you tell the difference between those who qualify and those who don't.

Interviewed by Sky's Dermot Murnaghan recently, David Davis seemed implausibly confident that he'd be able to tell the difference: "We have records," the noted anti-database state warrior said ominously.

Well David, I'm not entirely convinced that you do. HMRC records will be some help in dealing with the easy cases, but beyond that you'll need the utility bills, bank records etc that the residence certificate requires. Nor are entry and exit records likely to be of much help. In September of last year the government had advance data on around 86 per cent of people entering the country, while prior to the reintroduction of exit checks in April of last year 80 per cent of departures were covered. Assuming Brexit in 2019 the Home Office might theoretically have entry and exit data at that level or better covering four years, but it would need to improve its ability to match it up.

Last year in its report, E-borders and its Successor Programmes, the National Audit Office found that: "Relying on legacy systems means that current processes involve extensive manual effort, duplication of effort and restrictions on the use that can be made of travel history records". So yes, useful data probably exists, but no, using it is going to be tricky.

Aside from the logistical difficulties of doing anything meaningful with the count them all in, count them all out data we're already gathering, it's possible we could run into legal issues, depending on what we do. Say we set a cut-off date prior to final Brexit date, and we start logging new entrants after that cut-off date. Skip over how you tell the difference between Chantalle coming back from visiting her mum and an actual new entrant, and skip over you'd probably have to mod the border systems in order to be able to do that - wouldn't you be discriminating here? Under EU and British law new entrants have precisely the same rights as everybody else, so your only option is to log everybody.

And build the systems that didn't get built because E-borders got terminated. There are enough wise heads in government, surely, to know lobbing another giant IT catastrophe into the Brexit mess would be a very foolish thing to do indeed. Essentially, all that's sane argues for any cut-off date to be Brexit day, with the possibility of freedom of movement being extended beyond that, depending on negotiations.

We will at least initially not be significantly closer to differentiating between new entrants and existing residents once we get to that day. As the years go by, provided our ability to use border data improves, then we'll gradually get better at that. Employers will also be some use, because once we've exited they will need to establish right to work for EU citizens in the same way as they do for non-EU. But we'll need to have issued the paperwork that lets them do that before we start insisting (see permanent residency certificates).

So, not a lot changes, EU citizens wanting to live and work in the UK don't really have a lot to worry about for quite some time to come*, and although we can squeeze EU migration over the years, we've been embedded in the EU for sufficiently long for it to be costly to control the numbers in the way some Brexiteers wanted. Did you really say that David? That was unwise.

Realistically, a period of EEA membership post-Brexit makes a lot more sense than any of the other options, but it would mean free movement continues for say, another five years. Given that he's supposed to be figuring this out, it's possible that David Davis can be convinced, or will end up convincing himself, that zero EU immigration can be kicked down the road into the distant future. But those who campaigned and voted for immigration control? How ready are they to accept that it can't be done, we can't afford it? Awkward. ®

*Warning: the author is not an immigration lawyer.