The so-call Irish backstop is designed to keep an open border between the United Kingdom's Northern Ireland and EU member state Ireland. Many U.K. lawmakers, particularly in Prime Minister Theresa May's Conservative Party, say it could keep Britain tied to the EU for too long, even indefinitely. Some are arguing that the planned transition period, whereby Britain follows the rules of the European single market for a period after the scheduled March 29 exit date, is extended until the end of 2021 to give negotiators time to thrash out an alternative plan.
"We need this backstop because it is the only insurance to avoid a hard border at the moment. But we are ready, during the transition, if we have a transition, to work on the alternative arrangements," Barnier said in the Netherlands.
May is currently discussing "alternative arrangements" to the backstop with members of her own party.
Ireland's foreign minister, Simon Coveney, has warned about Britain's "wishful thinking" when it comes to finding alternatives to the so-called Irish backstop, which is holding up a Brexit solution.
Coveney said Monday that during the 17 months of talks on the draft withdrawal agreement many scenarios for the Irish border were looked at. But he said that beyond the one Prime Minister Theresa May agreed on, and which was rejected by the U.K. legislature, none were workable.
The changes center on replacing a measure known as the backstop, designed to keep an open border between the United Kingdom's Northern Ireland and EU member state Ireland. Some U.K. lawmakers fear it would keep Britain tied to the EU for too long, even indefinitely.
Coveney said no other option is available.
He said: "What Ireland is being asked to do by some in Westminster is to essentially do away with an agreed solution between the U.K. government and EU negotiators and to replace this with wishful thinking."
A Dutch judge has refused to hear a case brought by four British citizens who live in the Netherlands seeking to clarify their citizenship rights after Britain leaves the European Union.
The judge in Amsterdam ruled Monday that the case brought by the four Britons was inadmissible as it should be considered by a special immigration court.
Lawyer Christiaan Alberdingk Thijm says his clients are "very disappointed" with the rejection.
They wanted the court to ask the European Union Court of Justice in Luxembourg to issue a ruling that would have clarified the post-Brexit rights of all British citizens living on mainland Europe.
Alberdingk Thijm says he will consult his clients before deciding whether to take the case to an immigration judge.
A leading global tourism body estimates that around 700,000 jobs in travel and tourism could be lost across Europe if Britain crashes out of the European Union without a deal on future relations.
The World Travel & Tourism Council said Monday that 308,000 jobs would be under threat in Britain and 399,000 elsewhere in Europe.
The WTTC, which represents the travel and tourism sector worldwide, based its assessment on the forecast from the International Monetary Fund that the British economy will be 7.7 percent smaller over the next decade in a 'no deal' scenario.
Gloria Guevara, President & CEO, WTTC, said "a 'no deal' Brexit would have a dramatic impact on one of the U.K.'s most significant sectors."
Britain is due to leave the EU on March 29.
German Chancellor Angela Merkel is suggesting it's still possible for the European Union and Britain to come to an agreement on how the border between Ireland and the U.K's Northern Ireland will function after Brexit, but says London needs to come forward with a proposal.
Speaking Monday during a trip to Japan, Merkel said the already-agreed Brexit withdrawal agreement can't be renegotiated. But she said questions surrounding the border arrangements could be addressed in a declaration on the future relationship between the EU and Britain.
She says "one has to be creative, and we must listen to one another" but that an agreement on the Irish border is still possible.
But first, Merkel says "we must hear from Great Britain how they envision that."
With Brexit just seven weeks away, Britain's ruling Conservative Party was negotiating with itself Monday in an attempt to rework Britain's divorce deal with the European Union.
Meanwhile, pro-EU and pro-Brexit politicians traded allegations about whether Nissan's decision not to build a new SUV in northern England was the latest sign of Brexit-induced economic damage.
Prime Minister Theresa May was gathering pro-Brexit and pro-EU Conservative lawmakers into an "alternative arrangements working group" seeking to break Britain's Brexit deadlock.
The group is holding three days of meetings with ministers and civil servants to investigate possible changes to the divorce deal rejected by Parliament last month.
The changes center on replacing a measure known as the backstop, designed to keep an open border between Northern Ireland and EU member Ireland.