European Union negotiator Michel Barnier told Britain Tuesday it cannot have an open-ended post-Brexit transition, and warned that a deal on the phase remained out of reach.
Barnier added ahead of a key speech by Prime Minister Theresa May on future trade relations that Britain's plans for privileged access to the single market, including for cars and medicines, were "cherry picking".
"There are quite a lot of points of disagreement. I regret, but maintain the evaluation I made a few weeks ago: in the light of these disagreements, we have not achieved the transition yet," Barnier told a press conference after briefing EU ministers.
Britain hopes to agree by an EU summit at the end of next month on a transition period during which it will still follow EU laws in exchange for access to the single market.
The EU says it should last until the end of 2020, when its current multi-year budget runs out.
But Britain says it should be "about two years", while a recent government paper said the date should reflect whatever time is needed for both sides to strike a deal on future trade ties.
Barnier noted that Britain "it seems would like to keep an open-ended transition, which of course is not possible".
"I think it's got to be clear that the transition period must be short," Barnier added in a warning shot to London.
The former French minister added that he was open to discuss matters "straightaway" with his British counterpart David Davis.
Barnier said deep divisions also remained on citizens rights for EU migrants moving to Britain during the proposed 21-month transition, as well as the UK's ability to object to new laws passed during the phase.
Further skewering London, Barnier said he stood by comments by EU President Donald Tusk on Friday in which he dismissed ideas for post-Brexit relations devised by the British government as "based on pure illusion".
"The answer is yes. I agree with the president of the European Council," Barnier said.
"We can't possibly imagine a situation in which we would accept cherry-picking," he added. "The UK knows what the rules are because they've been helping us to put them together for the last 40 years."
Barnier spoke a day before he will unveil the EU's draft of its Brexit divorce agreement, which will spell out in detail the agreement reached in December on three key topics: the fate of expatriate citizens, the financial settlement of divorce and the future of the Irish border.
The last pillar is the most sensitive, and all eyes will be on how the Brussels negotiators draft a key passage guaranteeing undisturbed ties between Northern Ireland and EU-member Ireland after the divorce.
Barnier acknowledged the 120-page draft would "render operational" a controversial "backstop" opposed by London on the issue of how to avoid a hard border between Ireland and British-ruled Northern Ireland.
The fallback option says that if no better solution is found, Northern Ireland would remain in "full alignment" with the EU's single market and customs union in order to uphold a 1998 peace agreement in the north.
"The Irish question cannot remain unresolved," Barnier said.