European Union's chief Brexit negotiator Michel Barnier | Olivier Hoslet/EPA Brexit talks to start Monday The top EU and UK negotiators will begin as scheduled in Brussels, despite British political turmoil.

U.K. Brexit Secretary David Davis and the EU's chief Brexit negotiator Michel Barnier agreed on Thursday that talks on Britain's departure from the European Union will begin on schedule on Monday June 19, two EU sources familiar with the matter told POLITICO.

The U.K. government and the European Commission confirmed the start date, with the Brits saying the talks would be led by Davis.

The agenda for Monday's talks is yet to be finalized, according to an EU source familiar with the preparations. The meeting is scheduled to run from 11 a.m. to 6 p.m. — "Brussels time, of course," the source said.

Barnier will speak English but wants the option of switching to French, so translation will be provided, the source said.

The timetable for the talks getting started had been thrown into doubt by last week's election setback for U.K. Prime Minister Theresa May. Her Conservative Party lost its parliamentary majority in a snap election that she had called to seek a stronger mandate for the Brexit negotiations.

However, British officials have insisted since the vote that they would stick to the timetable, which would enable May to attend a summit of EU leaders next Thursday and Friday with the negotiations already under way. Brexit is on the agenda of the summit, as well as the agenda of ministerial meetings earlier in the week to prepare for leaders' talks.

Confirmation that the negotiations will start on time came as the EU’s deputy Brexit negotiator Sabine Weyand held talks with U.K. officials in Brussels on Thursday — a meeting described by a European Commission official as "talks about talks."

May’s EU adviser Oliver Robbins was in Brussels on Monday for a working lunch with the EU's chief Brexit negotiator, Michel Barnier.

However, further details about the talks were thin on the ground.

At a high-level panel discussion on Brexit at the 2017 Prague European Summit, Stefaan De Rynck, an official in the European Commission's Brexit negotiation team, noted that in Barnier the EU has "a stable, mandated, accountable chief negotiator." It was unclear if the use of the word "stable" was a dig at Theresa May, whose campaign mantra was "strong and stable."

De Rynck, in response to a question, said he did not yet see any need to "lower the political temperature" around the talks. On the EU side, he said, "We're going to be rational about this, cool-headed, trying to find the common interests and see where the differences lie."

Martin Povejšil, the Czech Republic's ambassador to the EU, who also sat on the panel, said the EU was ready to talk. And while Brexit posed many challenging issues, Povejšil said he expected the EU27 to remain unified on the most fundamental positions. "Indivisibility of the four freedoms," Povejšil said. "If we stick to that, we are on the same side."

European Commission First President Frans Timmermans told the Prague event that the EU would be happy to see the U.K. change its mind and stay in the bloc. Asked if he supported statements by French President Emmanuel Macron and German Finance Minister Wolfgang Schäuble that the EU's door remained open, Timmermans said: "By all means; we didn't ask the U.K. to leave."

David Herszenhorn, Quentin Ariès and Tom McTague contributed to this article.