EU diplomats have hit out at Britain’s failure to agree it must pay a hefty financial settlement for Brexit, suggesting the controversy will “stall” the talks.

The second round of the negotiations appeared to have run into trouble within 24 hours of resuming in Brussels, over the vexed issue of the so-called “divorce bill”

Michel Barnier, the EU’s chief negotiator, was preparing to tell the British side that the negotiations served little purpose until Britain engaged seriously with the issue of payments.

Michel Barnier encourages the UK to make haste in the Brexit negotiations

“Financial settlement is the priority,” one EU diplomat told the Politico website.

“The EU will not walk away from talks but will stall them. The impression we got so far is that the UK is not ready for these talks.”

Another EU diplomat said: “It is reasonable to expect the Brits to say something other than ‘we will not pay a penny.’ If that’s not the case, what is there to talk about?”

The warning comes after eyebrows were raised over David Davis, the Brexit Secretary, leaving the talks after just one hour on Monday.

Mr Davis made only a flying visit to Brussels, speaking with Mr Barnier for no more than 15 minutes, before heading back to London and leaving the negotiations to his officials.

The agenda for the four-day talks includes the rights of EU citizens in the UK – and British ex-pats in the EU – the exit bill and the Northern Ireland border.

David Davis arrives for 2nd round of EU talks

Last week, Mr Barnier urged the British side to present detailed proposals on all three priorities before the talks resumed, but there is no evidence that this happened.

The Prime Minister’s official spokesman, asked about the diplomats’ criticism, said: “I haven’t seen those comments.

“Negotiations are ongoing and, as I have said throughout, we are not providing a running commentary on it.” Ms May was updated “all the time”, he added.

The European Commission declined to comment on the state of the negotiations, but said a working group on the UK’s financial settlement had convened as planned.

The Government has sent out mixed messages about its willingness to pay a large financial settlement in recognition of its past and future commitments.

The Brexit department acknowledged last week that there would be “obligations” even after departure day – but Foreign Secretary Boris Johnson told MPs the EU could “go whistle”.

The EU has refused to put a hard figure on the financial settlement it is demanding, amid claims it could run to €100bn.

In pictures: European parliament Brexit discussions Show all 12 1 /12 In pictures: European parliament Brexit discussions In pictures: European parliament Brexit discussions European commission member in charge of Brexit negotiations with Britain, French Michel Barnier listens at the President of the European Commission Jean-Claude Juncker speaking at the European Parliament in Strasbourg Getty Images In pictures: European parliament Brexit discussions Frank-Walter Steinmeier, President of the Federal Republic of Germany, delivers his speech at the European Parliament in Strasbourg EPA In pictures: European parliament Brexit discussions European Union's chief Brexit negotiator Guy Verhofstadt, President of the Group of the Alliance of Liberals and Democrats for Europe (ALDE), addresses the European Parliament during a debate on Brexit priorities and the upcomming talks on the UK's withdrawal from the EU Reuters In pictures: European parliament Brexit discussions Michel Barnier, European Chief Negotiator for Brexit reacts during a meeting at the European Parliament in Strasbourg EPA In pictures: European parliament Brexit discussions Member of the European Parliament and former leader of the anti-EU UK Independence Party (UKIP) Nigel Farage wears socks with Union Jack flag at the European Parliament in Strasbourg Getty Images In pictures: European parliament Brexit discussions Nigel Farage, United Kingdom Independence Party (UKIP) member and MEP, addresses the European Parliament during a debate on Brexit priorities and the upcoming talks on the UK's withdrawal from the EU Reuters In pictures: European parliament Brexit discussions European commission member in charge of Brexit negotiations with Britain, French Michel Barnier gestures during speeches at the European Parliament in Strasbourg Getty In pictures: European parliament Brexit discussions The President of the European Commission Jean-Claude Juncker (L) speaks with European commission member in charge of Brexit negotiations with Britain, French Michel Barnier at the European Parliament in Strasbourg Getty In pictures: European parliament Brexit discussions European Union's chief Brexit negotiator Guy Verhofstadt, President of the Group of the Alliance of Liberals and Democrats for Europe (ALDE), addresses the European Parliament during a debate on Brexit priorities and the upcomming talks on the UK's withdrawal from the EU Reuters In pictures: European parliament Brexit discussions Member of the European Parliament and former leader of the anti-EU UK Independence Party (UKIP) Nigel Farage gestures during speeches at the European Parliament in Strasbourg, eastern France, on April 5, 2017. The European Parliament will on April 5 lay down its "red lines" for negotiations over a Brexit deal, on which the assembly will have the final say in two years' time. / AFP PHOTO / Sebastien BozonSEBASTIEN BOZON/AFP/Getty Images Getty In pictures: European parliament Brexit discussions German president Frank-Walter Steinmeier delivers a speech during a plenary session at the European Parliament in Strasbourg Getty In pictures: European parliament Brexit discussions The European Parliament in Strasbourg, eastern France Getty Images

Mr Davis’ officials insisted it had always been the plan for him to open the negotiations, leave his team to handle the detailed talks and return to Brussels on Wednesday afternoon.

They denied he had been forced to return to Westminster early because Labour had forced an emergency debate and the Conservatives lacked a majority.

Labour’s shadow Brexit secretary, Keir Starmer, said the Government was in disarray over the Brexit talks. “The clock is ticking and the risks are increasing day by day.”