Much of the future border arrangements between Northern Ireland and Ireland can be solved before Brexit talks enter the next phase, Ireland's foreign minister said, urging Britain to be realistic in negotiating terms to leave the European Union.
British officials arrive in Brussels on Monday to push the EU towards talks about their post-Brexit ties, which the bloc refuses to do without an agreement first on London's exit bill and other divorce issues.
Among those issues is the conundrum of the currently invisible border between EU member state Ireland and Britain's province of Northern Ireland, a matter fraught with economic consequences and politically complexities.
"We want some realism. There is a suggestion in the British government papers on Ireland that really the Irish border issues can only be solved in the context of a free trade agreement and I think there is a lot we can do in advance of that," Irish Foreign Minister Simon Coveney told national broadcaster RTE.
As part of a series of papers published by London this month it hopes will push forward talks with the EU, Britain said there should be no border posts or immigration checks on the neighboring island of Ireland once London quits the EU in 2019.
At the same time, Britain's Conservative government intends to regain complete control over immigration as part of Brexit, raising questions how this would work if there was a "back door" into Britain along an open land frontier with Ireland.
The Irish government, which had grown critical of Britain's approach to the talks, welcomed what it called significant progress in the papers but reiterated on Monday that London now must spell out in detail how their plan could be implemented.
"It's up to the UK this week to outline how the position papers, particularly in relation to Ireland and the border issues, can actually work," Coveney said.
"Many in the EU, while they accept what Britain wants, they don't see how the negotiating approach can achieve that."
The European Parliament's Brexit point-man, Guy Verhofstadt, has dismissed the British government's outline approach, calling the idea of an invisible border a "fantasy."
The issue of how the Irish Republic and Northern Ireland will fare after Britain leaves the EU is particularly sensitive given the decades of violence in the province over whether it should be part of Britain or Ireland.
Around 3,600 people were killed before the 1998 peace agreement between pro-Ireland Catholic nationalists and pro-British Protestant unionists.
This story was reported by Reuters.