As published in the Times, July 2018.

We keep hearing it: Brexit means Brexit. A hard Brexit. A soft Brexit. A cherry-picked, fantastical Brexit. Perhaps increasingly likely, a no-deal Brexit.

This mess may be of the UK’s making, but borders are not impervious to spilt milk. Souring as it flows, that mess will meander its way into Ireland.

While we are hearing plenty about the customs consequences of, and contingency plans for, a no-deal Brexit, it has to be asked: what about the people? Irish people in the UK. British people in Ireland. Irish and British people living either side of the presently invisible Irish border. It would be naive not to be concerned about the status of all these people after March 29 next year if there is no deal.

We have been lulled into a false sense of security about this by the consensus between Ireland, the UK and the EU that the common travel area should be retained after Brexit. In a no-deal context, though, everything is on the table again. Contingency planning needs to extend beyond planes and customs and must extend to security for workers and businesses.

To take one example, under present rules, when an Irish-based company applies for or seeks to renew a work permit for a non-European Economic Area (EEA) national, it must establish that it has a ratio of at least 50 per cent EEA employees to non-EEA employees, known as the 50:50 rule.

After a no-deal Brexit, when the UK becomes a non-EEA country, companies may find their previously compliant ratios thrown off kilter. If Barney’s Inc has three employees from the UK, two from France and five from Argentina pre-Brexit, that is five from the EEA and five non-EEA. It meets the 50:50 rule.

In a no-deal Brexit, that ratio becomes 2:8. Barney has run foul of the 50:50 rule and must decide whether to employ six extra EEA staff to retain his eight British and Argentinian employees, or to let go of six of them. Either scenario will have a significant impact on the business, as well as on the Britons and Argentinians whose jobs may be on the line.

This outcome would arise even if British nationals did retain an unfettered right to work in Ireland after a no-deal Brexit. Even that cannot be taken for granted.