The inclusion of the December 2021 date in the latest government document on the Temporary Customs Arrangement, as it has become officially known, is thought to have been a response to demands for a clear time limit from Brexit Secretary David Davis.
Less than half of all people in Northern Ireland consider themselves British, according to a new survey.
Mr Barnier said that "much remains to be done" on the withdrawal issues of data protection, geographical indications for food and drink and the resolution of proceedings relating to the United Kingdom which are ongoing at the end of the transition period.
In a recording obtained by BuzzFeed news, Foreign Secretary Boris Johnson was quoted as telling Conservative party donors that May's government is ready to start playing hardball with the EU, just three weeks before Brexit is discussed among European leaders.
A source close to Mr Davis said: "Obviously, there's been a back and forth on this paper, as there always is whenever the Government publishes anything".
"I think Theresa is going to go into a phase where we are much more combative with Brussels", Johnson said.
The UK will leave the European Union on March 29th, 2019.
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In a statement announcing Greenwalt's resignation, Pruitt called her a "tremendous leader" within the agency. CNN has reached out to the EPA for comment and has not yet received a response.
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Seemingly still shaken, Whittaker was able to target a few big elbows that landed clean but couldn't halt the attack. Whittaker showed incredible resolve in survival, crawling again to his feet and trying to peel away the arms.
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Along with the impact on pork, the trade retaliation also affects $387 million in USA cheese sent to Mexico, the report said. A net importer of US steel, Mexico is also putting 25 percent duties on a range of American steel products.
The Daily Mail last month ran a front-page headline on Best for Britain's plan reading: "Plot to subvert Brexit exposed".
The prime minister also confirmed the trade and customs bills will also return to parliament soon, which contain amendments likely to give MPs another chance to vote on the issue of maintaining a customs union.
The May proposals also failed to address the need for full regulatory alignment on either side of the border, he added.
But Mr Barnier said the proposal raised a number of relevant and hard issues.
The PM must settle the Ireland issue at home to allow her negotiator Oliver Robbins to engage on it with Michel Barnier, the European chief negotiator.
But with major sticking points over the Northern Irish land border with the Republic of Ireland and over a future agreement for financial services, some British officials have suggested the outlines of a deal will not be announced until later in the year. "Is it an all-weather backstop?"
Brexit talks have been stalled in Brussels over the question of how to avoid a hard border at the Irish frontier.
The most contentious changes center on Britain's future economic relationship with the EU. "However, it remains vital that a legally-binding backstop is agreed to provide certainty that, in all circumstances, a hard border will be avoided", he said. The EU says ensuring the same rules apply across the island of Ireland in areas such as goods, agriculture, energy, electricity, and environment policy will be crucial to avoid border checks.