Leaving the EU means there would have to be border controls between Ireland and Northern Ireland.
That’s a matter of speculation at the moment. Some sort of customs checks on goods crossing the border would be needed, but not necessarily passport checks or stopping everyone.
“There would have to be border controls but not a prevention of genuine Irish from coming in across the border”
Lord Lawson, Vote Leave campaign, 10 April 2016
“I think that the land border we share with Ireland can be as free-flowing after a Brexit vote as it is today”
Theresa Villiers, Secretary of State for Northern Ireland, 17 April 2016
“The fear in Dublin is that our border towns would become a backdoor into the UK. In that instance what sort of fortress would the Northern Ireland border have to become to close that backdoor?”
Phil Hogan, European Commissioner for Agriculture, 9 May 2016
We don’t yet know what will happen to the border between the Republic of Ireland and the UK once the UK leaves the EU.
Reports suggested that the UK and EU were close to a deal in December 2017. However, the DUP said the proposal was “not going to be acceptable” as it would create a border between Northern Ireland and the rest of Great Britain, in order to keep the border open between Northern Ireland and the Republic of Ireland.
Nothing has yet been agreed. Claims that there will or won’t be border controls on the island of Ireland are predictions, not facts, at this stage.
We can show why it’s been raised as a real possibility, though.
Movement between Ireland and the UK now
People can also move freely around the UK, Ireland, Isle of Man and Channel Islands within the Common Travel Area. That means there are no official passport checks for someone travelling from Dublin to Belfast to London.
Why might the open border change when we leave the EU?
Ireland has no plans to leave the EU like the UK is in the process of doing. Brexit means that the UK’s only land border will also be an external border from the EU’s point of view.
That matters for two reasons. One is immigration and the other is trade in goods, neither of which have many controls on them within the EU.
We don’t know yet what arrangements will be worked out on these issues, so whether border controls would have to be re-established is still a matter of speculation.
What’s been happening in the latest negotiations?
In March 2018, the EU published a draft withdrawal agreement, effectively setting out its preferred deal, and highlighting text that it understands to already be agreed with the UK. The passages relating to the Irish border have not been agreed to by the UK.
The EU proposed a “common regulatory area” comprising the EU and Northern Ireland, and that the “territory of Northern Ireland” (excluding territorial waters) be considered to be inside the Customs Union. This would mean that Northern Ireland would still effectively be inside the customs union, even if the rest of the UK was out. This would mean there would be no need for checks at the Irish border, but there could be checks between Northern Ireland and the rest of the UK.
In the same month, Theresa May said: “Just as it would be unacceptable to go back to a hard border between Northern Ireland and Ireland [after Brexit], it would also be unacceptable to break up the United Kingdom’s own common market by creating a customs and regulatory border down the Irish Sea.” She described this as her “personal commitment”.
The Prime Minister also said that “The UK has been clear it is leaving the Customs Union” and “We are leaving the single market”. These two arrangements underpin the free movement of goods across the Irish Border. The EU’s chief negotiator, Michel Barnier, said in February “a UK decision to leave the single market, and to leave the customs union, would make border checks unavoidable.”
The government and the EU were apparently close to a deal on the issue in December 2017. We don’t know exactly what the draft proposals were.
However, upon seeing a draft of the agreement, the Democratic Unionist Party (DUP), the largest party in Northern Ireland, said it felt that the agreement “was not going to be acceptable” for them as the terms were “making a red line down the Irish Sea”.
This term refers to there being border controls between Northern Ireland and the rest of Great Britain. The DUP thinks such controls would occur because of the proposal’s intention for Northern Ireland to have some “regulatory alignment” with the rest of Ireland in order to keep the border free of controls.
This would mean that there would be different conditions in Northern Ireland, closer to Irish (and therefore EU) standards, compared with the rest of the UK.
Others, including the leader of the Scottish Conservatives, have called for such regulatory alignment with the EU to apply to the UK as a whole.
Checks on immigration are possible but it’s hard to forecast
World War II aside, there have never been controls on migration between the UK and Ireland.
The Common Travel Area means “minimal or non-existent border controls”, in the words of an Irish parliamentary report.
In practice the land border is almost completely open, but airlines and ferry operators still require photo ID, which doesn’t always have to be a passport. Passengers are always asked for passports at airports where immigration officers can’t tell that they’ve come from within the Common Travel Area.
Nevertheless, people can use the open border to travel illegally from Ireland to Northern Ireland and on to the rest of the UK, and likewise in the other direction.
This is currently addressed by “Operation Gull”, in which immigration officers check passengers on routes between Northern Ireland and the island of Great Britain. This is designed to compensate for the lack of checks on unauthorised travel across the north/south border.
It depends what restrictions the UK puts on EU immigration
Claiming this won’t change after Brexit assumes that these measures will still be enough to police the open border. Leave campaigners pointed out during the referendum that the Common Travel Area was in place before the EU even existed, and this has since been echoed by the Brexit Secretary.
This is true, but there’s never been a situation where Ireland accepted free movement of people and the UK didn’t.
If the UK wants to put restrictions on EU immigration or short visits, that might generate more illegal cross-border movement. At the moment, Operation Gull only has to catch unauthorised migrants from non-EU countries.
It’s at least possible that increased pressure on the border force will lead to a demand either for passport checks at the north/south border, or passport checks between Northern Ireland and the rest of the UK.
To be clear, a beefed-up border to keep out people who aren’t from the British Isles is different to there being restrictions on migration for British and Irish citizens. There’s been no suggestion that Irish people might lose the right to live and work in the UK, or vice versa.
Checks on goods are a more likely outcome
The official government position has been that “outside the EU’s Customs Union, it would be necessary to impose customs checks on the movement of goods across the border”. This is echoed by researchers at Open Europe and FactCheckNI, while there have also been concerns raised in Ireland.
This is because if there is no EU-UK agreement on free trade in goods, there would be some British taxes on imports from Ireland, and vice versa.
Without these ‘rules of origin’, and a way of enforcing them, goods made in a country like China could be imported through Ireland, avoiding UK import taxes.
So with or without a trade deal, you would need some way of checking on the goods being taken across the border, either to work out the taxes due on them or to verify that they don’t need to be paid.
Customs checks aren’t a big problem on the Norway/Sweden border
These checks could be fairly light touch. Because Sweden is in the EU and Norway is not, there are customs checks between those two countries.
They are spot checks, though, and don’t involve the checking of all vehicles.
Vans and lorries carrying imports could be told to attend a customs depot, which needn’t be at the border, with spot checks of commercial vehicles near the border as a deterrent against evasion. It might also be possible to use technology to reduce or eliminate the burden of physical checks.
Update 28 July 2017
We've updated the references in this article following the referendum result.
Correction 12 April 2018
We previously said passports were needed when crossing the Irish Sea, but some operators don’t require this specifically and accept other forms of ID.