Details of the UK’s plans for a transition period of “around two years” immediately after Brexit have been revealed in a leaked document.
Due to be officially published later, it says there are “only a small number of areas” where the two sides disagree.
It says the period should last as long as it takes to “prepare and implement the new processes and new systems”.
The BBC’s Norman Smith said much of the document would make “uncomfortable reading” for Tory Brexiteers.
It contains no “pushback” on EU demands for free movement of people to continue in the same form during the transition phase, no suggestion of a veto to block new EU laws and no power to implement new international trade deals without the EU’s permission, he said.
The document’s emergence comes after more than 60 Eurosceptic Tory MPs set out a list of Brexit demands for the prime minister – and a day before ministers meet at Chequers to try to thrash out a way forward.
The transition period is due to kick in as the UK leaves in March 2019, and is intended to give time to prepare for the long-term post-Brexit arrangements between the UK and the EU, which have yet to be agreed, and to give businesses time to adapt.
The EU has said the transition phase should end on 31 December, 2020.
Speaking on the BBC’s Daily Politics, Brexit Minister Steve Baker said “there will be a fixed date” for the end of this period, despite the document’s wording sparking claims it could be “open-ended”.
One area where the two sides have been expected to clash is citizens’ rights, and whether people from the EU arriving in the UK during transition will have an unrestricted right to stay.
The UK government has said such people should be treated differently to those who are already here before Brexit day – something the EU says it cannot accept.
BBC political editor Laura Kuenssberg said the leak suggested the UK “has softened its position”.
She added that the UK side thinks the positions are close:
Mr Baker said ministers “will need to collectively agree” on the rights given to EU citizens arriving during the transition.
He added: “We respect the freedoms of the European Union single market while we’re in the implementation period. That means people will need to come and go freely.”
The letter to Theresa May from 62 Tory MPs says the UK must not be stopped from negotiating trade deals with other countries, once it leaves the EU, and must gain full “regulatory autonomy”.
Earlier Labour leader Jeremy Corbyn said it was time for Mrs May to spell out clearly what kind of relationship she wanted with the EU after Brexit, accusing her of “waffle and empty rhetoric” at Prime Minister’s Questions.
“Businesses need to know. People want to know. Even Tory backbenchers are demanding to know.”
He suggested the PM had downgraded her negotiation goals from a tariff-free trade agreement to “as much tariff-free trade as possible”.
But Mrs May said this was not the case and her desired outcome remained a “bespoke economic partnership” with the EU which also enabled the UK to “take back control” of its laws, money and borders.
“We want to have a good trade agreement with the EU…but we also want to ensure this country takes the opportunities that will be open to us outside the EU to boost our economy.”
She rejected Mr Corbyn’s claims that Brexit would result in a “bonfire of regulations”, insisting the Conservatives record in government showed it was committed to protecting and extending workers’ rights.