What happens to the Irish border without a deal on Brexit?
The British and Irish governments have both stated that they are not preparing for a hard border between Northern Ireland and the Republic – so who is?
“No one,” according to the DUP’s deputy leader, Nigel Dodds MP.
“It was very significant when the Irish prime minister outlined his no-deal preparations, that there was no mention of any border infrastructure whatsoever,” he said.
“So many of us believe this whole backstop arrangement is totally unnecessary and is a political device.”
But David Phinnemore, a professor in European Studies at Queens University Belfast, says London and Dublin could face the demand for a border from elsewhere.
“Precedent suggests that the EU will insist that its internal market is protected and that will normally involve the external border existing so yes, I would imagine Ireland would come under pressure,” he said.
“As far as the UK is concerned, it may not necessarily be the World Trade Organisation that brings the pressure but it’s going to be a member of the WTO.
“They will want to ensure that the market they are sending goods to – the UK market – is a market which, if they have preferential access, that access is genuinely preferential,” he explained.
Irish Prime Minister Leo Varadkar has insisted on the backstop, despite the risk a no-deal Brexit poses for Ireland.
Irish Independent columnist Dearbhail McDonald, who grew up on the border, says this is about much more than customs.
“It’s maybe hard for people outside of Ireland to imagine,” she said. “It’s not just about trade or goods and services or inspections like security for immigration.
“This is fundamentally about people. It’s about peace and it’s about identity.”
Ireland could not accept any deal that risked a return to a hard border, but the DUP could not accept one that risked Northern Ireland’s position in the UK.
While the DUP holds the balance of power at Westminster, it was always going to be difficult for the prime minister to win enough support for the backstop.
It was barely mentioned during the referendum campaign but the border on the island of Ireland has become the defining issue.
The line on the tarmac, where Northern Ireland meets the Republic, could be the place where the prime minister’s withdrawal agreement reaches the end of the road.