The British government believes a Brexit deal is now “essentially impossible” following a testy phone call between Boris Johnson and German Chancellor Angela Merkel, the BBC reports. The British prime minister spoke to Merkel on Monday. An anonymous source from the prime minister’s office told the BBC that Merkel made clear a new deal based on Johnson’s demands was “overwhelmingly unlikely.” Johnson sent new proposals to European Union last week that put forward ways to remove the key sticking point from Theresa May’s deal—a plan to keep some some EU customs rules if that was the only way to prevent a hard border returning to the island of Ireland. It’s not clear how Johnson will proceed. He still insists the U.K. will leave the EU on the scheduled deadline of Oct. 31, despite legislation passed by British lawmakers last month that requires Johnson to write to the EU asking for a further delay if no deal is approved by parliament by Oct. 19.