Britain and the European Union on Monday reached a landmark deal on a transition phase that will last for almost two years after the historic Brexit divorce next year, EU negotiator Michel Barnier said.
Britain will stay in the single market and customs union for 21 months after it leaves the EU in March 2019 and will be able to sign new free trade deals during the transition - but they won't come into effect until after the period has ended, said the deal.
Britain also agreed in principle to the EU's "backstop" plan for the status of the Irish border, under which British-ruled Northern Ireland would remain part of the EU's customs union if there is no better idea.
As for citizens' rights, European citizens from the 27 states of the EU who arrive in Britain during the transitional period will have same rights as citizens who arrived before the Brexit, said the deal.
The DUP said in a statement there had been "no agreement" around how arrangements of any potential backstop or other border options would work.
While considerable progress had been made, both negotiators said differences remained over the UK-Ireland border.
It still can not, however, become bound by any such new trade deals before the transition period runs out, or it is specifically given permission by the European Union 27.More news: St Patrick's Day celebrations around the world as Chicago river turns GREEN
U.K.'s Brexit Minister David Davis said that this would allow businesses to plan.
All sides are united in their desire to create a frictionless border after Brexit and the issue is expected to dominate talks next week.
Davis talked up the future of EU-British trade relations because they would start from similar rules, standards and tariffs, even though no pact can start until after 2020.
After a weekend of intensive talks, the two sides issued a new 129-page draft treaty denoting final agreement on large areas of the legal text. The pound rose as much as 1 per cent against the dollar to $1.4088, its strongest since February 16.
Talk in Britain about quitting the EU's fisheries policy next year has also evaporated, with May accepting that the standstill transition - or "implementation period" as she calls it - meant full compliance with current rules. Brexit firebrand Nigel Farage said "Theresa the Appeaser" had "let people down again" by agreeing to European Union demands to keep free immigration during the transition. All have backed Irish demands on the border, although some of Britain's nearest neighbours, with most trade to lose from Brexit, also pushed for a quick transition deal to help their own businesses.
"In keeping with that commitment, we agree on the need to include legal text detailing the back stop solution for the border of Northern Ireland and Ireland in the withdrawal agreement that is acceptable to both sides", he said.
"The Brits have just given in on everything, so big was their drive to get the transition".