European Union leaders have issued increasingly stern warnings that Britain cannot have unfettered access to the single market after withdrawing from the EU without accepting the bloc's rules on free movement.
"There will be no single market a la carte," European Council President Donald Tusk said in Brussels on June 29 after a meeting of the 27 EU leaders without British Prime Minister David Cameron.
"Leaders made it crystal-clear today that access to the single market requires acceptance of all four freedoms, including freedom of movement," Tusk said of the trading bloc that currently eliminates borders and other regulatory obstacles among more than 500 million people.
The German and French leaders have said the same.
Tusk reiterated that negotiations on Britain's future relationship with the EU cannot start until the Lisbon Treaty's Article 50 exit procedure is formally triggered by the British government -- a step that Cameron and other British politicians have shown a reluctance to take despite the 52 percent-48 percent victory for the "leave" side in the country's June 23 referendum.
The former Polish prime minister also said there would be another meeting on September 16 in Bratislava, Slovakia, of EU leaders, excluding Britain, to discuss the implications of Britain's exit from the bloc.
The British vote dealt a heavy blow to fellow EU members and supporters of the decades-long effort to tie the political and economic fates of Europe together, and comes with a migration crisis tugging at the continent's seams.
German Chancellor Angela Merkel said Europe faced "a very serious situation" with Britain wanting to leave, but she added, "We think that we 27 can deal with this situation."
Merkel said that the lesson from the U.K. referendum isn't necessarily either deeper integration or returning more powers to national governments.
"This is not about more or less Europe as a principle, but about achieving results better," she said.
On June 28, Cameron attended what was expected to be his final EU summit, after he conceded defeat in the so-called "Brexit" referendum and announced his intention to stand down by October.
Cameron said there was "universal respect" for Britain's decision to leave despite a "tone of sadness and regret."
He said the British voters' decision couldn't be reversed despite street protests by thousands of pro-EU demonstrators in London and moves by the opposition Labour Party to force a second referendum.
Cameron also stressed that his country will not turn its back on Europe, saying trade and security cooperation would be vital whatever the future brings.
German Chancellor Angela Merkel and other EU leaders renewed their call for Britain to set out plans as soon as possible for leaving and insisted that there can be no negotiations before London has formally invoked the Lisbon Treaty's Article 50 exit procedures, which set a two-year deadline for agreeing the trade and other terms of an exit.
The leaders also said they would give Britain some time to put new leadership in place and start the process of carrying out the withdrawal, while making clear that they would take a strict stand in negotiations with London over post-Brexit relations.
Britain "has collapsed, politically, monetarily, constitutionally, and economically," Rutte said. "It would be unreasonable to insist. Let them get their political house in order."
"Europe is ready to start the divorce process, even today," EU Council President Tusk said, adding that he understood that time was needed "for the dust to settle" in Britain before the next steps can be taken.
But European Commission President Jean-Claude Juncker warned that Britain did not have "months to meditate," saying London could activate Article 50 shortly after Cameron's successor takes office.
Over dinner with the other EU leaders, Cameron urged them to consider reforming the EU's rules on freedom of movement, a central tenet of the economic bloc, saying he believed that free movement was "one of the driving factors in people voting to leave."
French President Francois Hollande rejected that suggestion, saying continued access to the EU's prized single market was dependent on accepting the freedoms of movement of goods, capital, workers, and services.
"If they don't want free movement, they won't have access to the single market," he said.
"Whoever leaves the family can't expect the same privileges as it had before without also having the obligations," according to Merkel.
Later on June 29, Juncker will meet in Brussels with Scottish First Minister Nicola Sturgeon, who has announced plans to defend U.K. member Scotland's place in the EU and was given a formal mandate by the Scottish parliament for direct talks with EU institutions.
Sturgeon held talks earlier in the day with European Parliament President Martin Schulz, after which she declared, "Scotland is determined to stay in the EU."
Schulz said he had "listened and learned."
Scotland is to draw up legislation for an independence referendum to ensure it could be held during any negotiations for Britain to leave the bloc.
Cameron has rejected the initiative, saying Scottish voters already rejected independence in a 2014 referendum.
Fellow U.K. member Northern Ireland also voted overwhelmingly to remain in the EU.