Addressing a news conference at the European commission after a full day of talks, Barnier told reporters: “We have to remember that it is the UK that has chosen to leave the EU. It is not the other way round.
“The consequences of this are going to be very substantial and we should not under estimate this. The aim of these negotiations should be to minimise the negative impact of Brexit.
“We are going to have to unravel a partnership that has taken 43 years to build. But I want to stress that this is not about punishment or revenge. In our efforts to find an agreement, I personally will put emotions to one side and stick to the facts and figures.”
With fears that the UK side may prefer to keep ongoing details of the talks private, the former EU commissioner and MEP also called for “full transparency” as the negotiations progress, will full disclosure of all relevant documents.
He said, “We do not want any leaks.”
Barner also repeated the EU mantra that “sufficient progress” will have to be made on citizens’ rights, the UK divorce bill and the Irish border issue before moving to talks on trade and the UK/EU future relationship.
“There must be sufficient progress but we are wanting the strongest possible partnership with the UK,” said Barnier.
Barnier noticeably dodged a question about whether, with Westminster gripped by political uncertainty caused by the recent UK election, he thought he would still be facing Davis in 12 month’ time.
On the issue of the Irish Border, Barnier said we should “preserve all the dimensions and commitments of the Good Friday Agreement” and maintain the UK-Ireland common travel area. He added, “The other problem in parallel with that is that without creating a new hard border, at the same time we have to come up with solutions – especially for goods and services – but in a way that is compliant with the normal rules and integrity of the internal market.”
Speaking alongside Barnier at the same news conference, Davis sought to answer questions about the UK’s Brexit position, saying, “The UK parliament has, quite rightly, been asking our government this same question.”
He indicated that Britain still sought a “hard” Brexit whereby it will leave both the single market and customs union.”
Davis also said it was the UK’s aim to be “as transparent as possible”, adding, “We want to see the public informed in the widest possible sense about what is happening.”
Davis announced that Prime Minister Theresa May will update EU leaders on the UK’s approach to citizens’ rights later this week at the European Council summit; the UK will also publish a detailed paper on Monday on the offer.
However, critics said the UK negotiating position still remains unclear.
The two sides have agreed to hold talks, each time lasting up to one week, every month.
Speaking on the conclusion of the first day of Brexit talks, Labour's leader in the European Parliament Glenis Willmott MEP said: "David Davis has begun some of Britain's most important negotiations for a generation, yet the British people still have no information about what he intends to negotiate.
"Britain needs a government that will proudly declare it will do what is best for jobs and the British economy. We need a government that understands the anguish of people whose homes and livelihoods depend on the outcome of the talks. Instead, we have a weakened Prime Minister who can't even publicly say what she wants to achieve.”
She added, "It is in the country's interests for there to be a real change of tone from the British government in its approach to the negotiations. But the real test of David Davis is not just one of tone. With the clock ticking on Britain's membership of the EU single market and customs union, on which so many British and EU jobs depend, we need to start seeing progress on the substance of the negotiations, not just timetables and procedure."
Meanwhile, Germany's Foreign Minister Sigmar Gabriel signalled that the UK may be able to secure a soft Brexit that keeps the UK in the single market after it has officially left the EU.
Gabriel also indicated a deal could be done on the jurisdiction of the European Court, allowing Theresa May to fulfil her pledge to end its jurisdiction while also meeting the EU’s needs.
Gabriel told the Welt am Sonntag newspaper in Germany that “maybe there is now a chance to achieve a so-called 'soft Brexit.'”
But the Social Democrat politician said staying in the single market would require the UK to at least accept EU workers' freedom of movement.