EU leaders say Britain has a final chance to leave the bloc in an orderly fashion, having given the UK parliament an April 12 deadline to offer a new plan or choose to quit the bloc without a treaty.
Arriving for a second day of a summit dominated by talks over Britain's departure, Belgium's prime minister said he hoped for a rational decision by British lawmakers to back the withdrawal treaty that May concluded with Brussels.
Preparations for a no-deal, in which Britain would face sudden trade barriers and restrictions on business, were still underway, however, Charles Michel told reporters on Friday.
"This is perhaps the last chance for Britain to say what it wants for the future," Michel said. "More than ever, this is in the hands of the British parliament," he said, adding that the 27 EU leaders were not blind to the risks of a no-deal.
Luxembourg's Prime Minister Xavier Bettel said he believed May, who did not attend the second day of the summit, had a 50:50 chance of getting the deal through the House of Commons.
"Hope dies last with me," Bettel said.
Seven hours of summit brainstorming on Thursday kept a host of options open for leaders, who say they regret Britain's decision to leave but are eager to move on from what they increasingly see as a distraction.
May, who addressed leaders on Thursday but missed out on the dinner because the 27 were forced to focus on Brexit rather than China, was kept in the loop by summit chair Donald Tusk, the European Council president, who shuttled back and forth.
Tusk explained the leaders' thinking to May and secured her acceptance for the plans, officials said.
May originally wanted to be able to delay Britain's departure until June 30 to tie up legislative loose ends.
But now, a May 22 departure date will apply if parliament rallies behind the British prime minister next week. If it does not, Britain will have until April 12 to offer a new plan or decide to leave the European Union without a treaty.
That date corresponds to the six weeks' legal notice required for the EU election - which the bloc would insist Britain hold on May 23 if it remains a member. If it does not hold the election, leaders said, the very last date Britain must leave would be June 30, before the new EU parliament convenes.
"We wanted to support May and we showed that," German Chancellor Angela Merkel told reporters. "It was an intensive, but successful evening."
The leaders have pushed the trigger back to Britain, which will be confronted with making a choice by April 12 on whether to hold an EU election as part of a long-term rethink, or prepare to quit by May 22, or possibly in June, without a deal.
"Everything is now in the hands of the House of Commons. That's the message," a senior EU official said.
Australian Associated Press