U.K. and E.U. Harden Their Positions on Brexit as G7 Meeting Nears

Similarly, it said, “The letter’s suggestion that two separate legal, political, economic and monetary jurisdictions already exist on the island and can be managed with an open border is misleading.”

Such words left a huge rift between the sides, just as Mr. Johnson was preparing to visit Chancellor Angela Merkel of Germany in Berlin on Wednesday and President Emmanuel Macron of France in Paris on Thursday. His trips are due culminate in more talks at a summit meeting of Group of 7 leaders this weekend in Biarritz, France.

On a rare note of guarded optimism, Ms. Merkel suggested Tuesday that a “practical solution” could still be found for the Irish border issue, making the backstop superfluous. But she said finding such a solution would not require reopening negotiations on the current Brexit deal.

Mr. Johnson has vowed that Britain will leave the bloc “come what may” on Oct. 31, with or without a deal aimed at softening the transition.

To that effect, Steve Barclay, Britain’s secretary of state for leaving the bloc, said Tuesday that the diplomatic corps “will only go to the (European Union) meetings that really matter, reducing attendance by over half and saving hundreds of hours.” He said that would free up time “to get on with preparing for our departure on October 31 and seizing the opportunities that lie ahead.”

But Mr. Johnson faces rising criticism of his Brexit strategy at home. A leaked report showed that the British government is preparing for widespread shortages of food, fuel and medicines in the event of a no-deal Brexit.

Jeremy Corbyn, the leader of Britain’s opposition Labour Party, vowed late Monday to do “everything necessary” to prevent Britain from leaving the European Union without a deal. That includes calling a no-confidence vote in Mr. Johnson’s government and, if it succeeds, competing in the ensuing general election with a pledge to hold a second public vote on Brexit.

After a 2016 referendum in which the public voted to leave the European Union, Mrs. May spent more than two years negotiating a Brexit divorce agreement with the bloc. It was repeatedly rejected by British lawmakers, primarily because of concerns about the Irish border.