The European Union’s chief Brexit negotiator, Michel Barnier, issued his second stern warning to the U.K. in the space of a week, demanding Theresa May’s government make its positions clear so talks on its withdrawal from the bloc can start making progress. “We can’t remain idle as the clock’s ticking,” said an exasperated-sounding Barnier, when he briefed journalists in Brussels on Wednesday. “We need to know on which points we agree and on which points we disagree so that we can negotiate in earnest.” More than three months since Britain officially triggered the start of Brexit talks and the two-year countdown to the U.K.’s departure began, the EU is still confused about what Britain’s red lines are and where it will compromise. The uncertainty is focused on the two issues that negotiators want to settle first: Britain’s financial obligations to the EU and the rights it’ll give to EU citizens in the U.K. after Brexit. The U.K. needs “sufficient progress” on these, as well as the status of the border with Ireland, before preliminary talks on a trade agreement can begin, penciled in for later in the year. British Ambitions But Barnier said it was unthinkable that such talks could start while Britain was unclear about its ambitions. “How do you build a relationship that is going to last with a country where you don’t have trust? How would you do that?” Barnier asked. “Trust means giving security to the 4 million British and European citizens; it means settling accounts.” The so-called Brexit bill was always going to be one of the most contentious issues. EU officials have indicated it could run as high as 100 billion euros ($115 billion) in gross terms as they push the U.K. to cover past budget commitments. The U.K.’s published position paper on citizens’ rights, which falls some way short of EU demands, is also adding to a sense of alarm in Brussels about the distance between the two sides so early in the process. Britain will publish three more position documents on Brexit on Thursday. One will cover the topic of Euratom, the nuclear safety watchdog. The EU has already published nine. In London, ministers struck a more positive tone than the one of frustration heard in Brussels. “Negotiations are going well,” First Secretary of State Damian Green, May’s deputy, told lawmakers in Parliament. “Fears of no deal are probably overstated.” Opposition parties are less convinced, however, with Labour’s foreign affairs spokeswoman Emily Thornberry accusing May of running out of ideas. “As a country, we have got 20 months to go until Brexit; we absolutely have got to get a grip,” she said in the parliamentary debate. “What a mess the government has got itself into by threatening to walk away even before talks began.” The talks could collapse because of a lack of preparation on the U.K. side, former Business Secretary Vince Cable, currently the only candidate to lead the opposition Liberal Democrat party, said in an interview with Bloomberg Television. Second Round Negotiations are scheduled to resume in Brussels on Monday. It’ll be the second time that officials on both sides meet face to face following a first round of talks last month. Barnier is scheduled to meet the head of Labour, Jeremy Corbyn, as well as the leaders of the Scottish and Welsh governments, in Brussels on Thursday. The U.K. is set to leave the EU in March 2019 whether it gets a deal or not and, if it doesn’t, it will be forced to accept World Trade Organization rules and sever all ties with the EU. Wednesday’s warning was Barnier’s second since the start of July. Last week, he cautioned the British government against thinking that any settlement could result in a “frictionless” trade relationship, saying however positive the deal is for Britain it will still have “significant consequences.” It was a rebuff to those in the U.K. who have seized upon May’s disastrous election performance last month when she lost her parliamentary majority as reason to think they can keep some benefits of membership. ‘Clock Ticking’ Earlier on Wednesday, Guy Verhofstadt, the European Parliament’s Brexit coordinator, struck a similar tone, saying he was still unsure whether the U.K. government has accepted it must foot a bill. “This uncertainty has, in my opinion, to disappear the fastest possible,” Verhofstadt told the Parliament’s constitutional affairs committee in Brussels. Speaking in the House of Commons in London on Tuesday, Foreign Secretary Boris Johnson said some of the Brexit bill sums being mentioned are “extortionate.” EU leaders can “go whistle” if they expected the U.K. to pay those sort of amounts, he said. In Brussels on Wednesday, Barnier referred to Johnson’s remark. “I’m not hearing any whistling,” he said. “Just the clock ticking.”