BRUSSELS - European leaders met Wednesday without Britain for the first time in 40 years to prepare for life after the Brexit bombshell, as the race began to succeed Prime Minister David Cameron.

Highlighting the seismic shock from last week's referendum, one person who was in Brussels however was Scottish First Minister Nicola Sturgeon, "utterly determined" to see Scotland remain in the EU.

Britain "made the decision that it did. And this morning it looks like they aren't sitting at the table any more," European Commission President Jean-Claude Juncker said as he arrived Wednesday. At a summit described as "sad" on Tuesday, Cameron won some breathing space from the remaining 27 leaders of the bloc five days after Britain rocked financial markets by voting 52 to 48 percent to leave the bloc. EU President Donald Tusk said he understood that time was needed "for the dust to settle" before the next steps can be taken.

However, Juncker warned Britain did not have "months to meditate" before triggering Article 50 - the EU treaty clause that begins the two-year withdrawal process - after Cameron's successor takes office in early September. And German Chancellor Angela Merkel warned that London could not "cherry-pick" the terms of the exit negotiations.

Some in Brussels are concerned that giving Britain favourable divorce terms will spark a domino effect of others leaving the union, set up six decades ago to foster peace on the continent after World War II. "We need more than ever a united Europe, in contrast to a disunited UK," Luxembourg's Prime Minister Xavier Bettel said Wednesday.

Cameron flew back to London after Tuesday's summit, as Sturgeon headed in the opposite direction to test the waters in Brussels for her country joining the bloc as a separate entity. Scotland overwhelmingly backed "Remain" in last Thursday's vote, and the combative Sturgeon has said she was "utterly determined to preserve Scotland's relationship and place within the EU".

That may require a new referendum on Scottish independence, with Sturgeon saying that the Britain from the last vote in 2014 "does not exist any more" following the Brexit vote. Sturgeon met on Wednesday morning with European Parliament President Martin Schulz and was to hold talks with Juncker later.

Top of the agenda at Wednesday's EU meeting was how the remaining 27 members can bolster unity after the shock of the British vote.

Meanwhile, both main political parties in Britain are in turmoil with the opposition Labour leader Jeremy Corbyn refusing to resign despite a crushing no-confidence vote. Within the governing Conservatives, nominations opened Wednesday for a successor to Cameron. The cut-off is noon on Thursday and the winner will be named on September 9.

Meanwhile, Prime Minister David Cameron, who promised to resign after Britain voted to leave the European Union, had some advice for his opposite number in the Labour Party on Wednesday: "For heaven's sake man, go!" An overwhelming majority of Labour lawmakers passed a no confidence motion in Jeremy Corbyn on Tuesday and almost all his senior policy team have withdrawn their support in protest at his leadership, but Corbyn has refused to step down.

Meanwhile, US Secretary of State John Kerry said on Tuesday that Britain's vote to leave the European Union might never be implemented and that London  is in no hurry to go.  Speaking one day after talks with Prime Minister David Cameron, Kerry said the outgoing British leader feels "powerless" to negotiate a departure he does not want.

 "This is a very complicated divorce," Kerry told the Aspen Ideas Festival, referring to Britain's negotiated exit from the EU after last week's "Brexit" referendum.

Kerry, who visited Downing Street on Monday, said Cameron was loath to invoke "Article 50" of the Lisbon treaty, which would trigger a two-year timetable for departure.

London, Kerry explained, does not want to find itself boxed in after two years without a new association agreement and to be forced out of the EU without one. And, he added, Cameron "feels powerless - and I think this is a fair conclusion - to go out and start negotiating a thing that he doesn't believe in and he has no idea how he would do it.

"And by the way, nor do most of the people who voted to do it," Kerry said, apparently referring to "Leave" campaigners such as former London mayor Boris Johnson, now the frontrunner to replace Cameron as premier.

Asked by the panel moderator if this meant the Brexit decision could be "walked back" and if so how, Kerry said: "I think there are a number of ways."

"I don't as secretary of state want to throw them out today. I think that would be a mistake. But there are a number of ways," he said.

Washington has long supported a strong role for its British ally in the European project, and was dismayed when British voters chose last week to quit the Union.

Now, US officials are calling for a calm debate on Brexit leading to a deal that would allow a close association between London and Brussels to continue.

Some EU leaders, however, insist that Cameron must move quickly to invoke Article 50 and begin divorce talks, to put an end to political and economic uncertainty.