David Davis, UK Secretary of State for Exiting the European Union, said on Friday that divorce talks between the EU and Britain have been “getting a bit tense”.
Mr Davis said in a speech in the US that he wants a Brexit outcome that is in “in everyone’s interests”.
However, he added that Britain is currently in a difficult and complicated negotiation period, which he described as “turbulent”.
Whilst there is no concrete figure regarding the amount the UK will have to shell out as a “divorce payment”, European Commission president Jean-Claude Juncker has said that it could be as much as 60bn euros (£55bn).
Mr Davis said: “What’s been going on is that we have got to the point today where there has been some pressure over the last couple of days, pressure over the question of whether we pay a divorce bill, a separation bill, and if so what it is.
“What we’ve been doing, as you do when someone provides you with a large bill, is go through it line-by-line. And we’ve got very good lawyers.”
He added: “We are in a difficult and tough and complication negotiation. I have said from the beginning it will be turbulent.
“What we’re having at the moment is the first ripple and there will be many more ripples along the way.”
His speech follows comments on Thursday by EU negotiator Mr Barnier in which he said some of the UK’s requests were “simply impossible”.
“We need UK positions on all separation issues. This is necessary to make sufficient progress. We must start negotiating seriously,” Barnier said.
“We need UK papers that are clear in order to have constructive negotiations and the sooner we remove the ambiguity, the sooner we will be in a position to discuss the future relationship and the transitional period.”