Monday's talks, however, come amid signs of increasingly serious splits within the United Kingdom government over the preferred approach to the talks, with the chancellor, Philip Hammond, complaining on Sunday that he was being briefed against by fellow ministers opposed to his pro-business focus. Earlier in March, British Prime Minister Theresa May had set a two-year timetable for leaving the EU.
Brexit negotiations resumed in Brussels on Monday against a backdrop of political infighting among British ministers over the terms of Britain's departure from the European Union.
They want to frustrate Brexit. In particular, the delegations are expected to focus on how to manage new border arrangements, what rights EU and United Kingdom citizens will hold post-Brexit and, most controversially, how much London owes the Union.
"We made a good start last month, and this week we'll be getting into the real substance", Davis was quoted by Reuters as saying ahead of the meeting.
Barnier said on Monday that the talks, which run to Thursday, would "delve into the heart of the matter".
Visa denial for Afghan girl roboticists team overturned
Without the reversal, the team would have had to watch the contest via video link from their hometown in Herat, Afghanistan. The Afghani robotics team will now be able to attend the FIRST Global Challenge robotics competition this weekend.
Barnier, who has repeatedly called on Britain to set out a full divorce strategy, said they needed to "examine and compare our respective positions in order to make good progress". Over the weekend he was subjected to briefings against him over a range of remarks he had allegedly made at a Cabinet meeting last week. Mr Hammond all but admitted a report he had told the cabinet that public-sector workers are "overpaid" was true - while denying he had said "even a woman" can drive a train. "Over the last few weeks, I've tried to advance ensuring that we achieve a Brexit that is focused on protecting our economy, protecting our jobs and making sure that we can have continued rising standards in the future".
Sources in Brussels were also more optimistic on the eve of the talks about avoiding a total breakdown in negotiations, after the United Kingdom formally recognised financial obligations to the European Union in a written statement to parliament last week. Unsurprisingly, the Brits have expressed opposition to these figures; Foreign Minister Boris Johnson labelled the sums "extortionate", saying Brussels can "go whistle" for the money.
Only when "sufficient progress" has been made on those matters will the European Union allow discussions to turn to trade.
During four days of talks the two sides hope to make progress on key issues surrounding Britain's withdrawal, including citizens' rights and its exit bill, so that negotiations can move on to discuss a future trade deal later this year. "It's a mess. Nobody would want to see them like this", said one European diplomat handling Brexit.
On Sunday, the former Tory chair Chris Patten warned that the Brexit deadlock represented one of the bleakest moments in British postwar history.