LONDON: The British government has said repeatedly that it will end the free movement of people from the European Union when the U.K. leaves the bloc in 2019.
On Wednesday it acknowledged that, in practice, it won't.
Britain said there must be no border posts or electronic checks between Northern Ireland and the Irish Republic after Brexit, and it committed itself to maintaining the longstanding, border-free Common Travel Area covering the U.K. and Ireland.
"There should be no physical border infrastructure of any kind on either side of the border between Northern Ireland and Ireland," Prime Minister Theresa May said.
That means free movement across the border for British, Irish and EU citizens. After Britain leaves the bloc, EU nationals will be able to move without checks from Ireland to Northern Ireland, and onto other parts of the U.K.
Free movement among member states is a key EU principle, and has seen hundreds of thousands of people move to Britain since the bloc expanded into eastern Europe more than a decade ago.
Many Britons who voted last year to leave the EU cited a desire to regain control of immigration as a key reason.
In a paper outlining proposals for the Northern Ireland-Ireland border after Brexit, the British government insisted it will be able to control immigration, because "immigration controls are not, and never have been, solely about the ability to prevent and control entry at the U.K.'s physical border."
It said control of access to the labor market and social welfare are also "an integral part" of the immigration system.
Northern Ireland is an especially thorny issue in Brexit talks, because it has the UK's only land border with the EU, and because an open border has helped build economic prosperity that underpins the peace process.
The Department for Exiting the European Union acknowledged "unprecedented" solutions are needed to maintain the benefits of an open border.
It suggested a future "customs partnership" between Britain and the EU could eliminate the need for border checks on good crossing the border.
The Northern Ireland proposals came in one in a series of papers covering aspects of Brexit negotiations, which are due to resume in Brussels at the end of this month.
The Irish government welcomed Britain's commitment to "avoiding a hard border" and said it would examine the proposals.
European Commission spokeswoman Annika Breidthardt said Britain's position papers — which come after allegations from EU officials that the U.K. is underprepared for divorce negotiations — are "a positive step."
"The clock is ticking and this will allow us to make progress," she said.