BOOST FOR "BREXIT"?

As EU leaders struggle to come up with a joint approach, their discord also bodes ill for attempts to find collective solutions to economic and environmental challenges such as reforming the euro zone or fighting climate change.

"The EU has trouble handling more than one problem at a time," said Tina Fordham, chief global political analyst at U.S. banking giant Citi, who considers the migration crisis a major source of political risk for Europe.

"Discord and backtracking over refugees and migration could end up fragmenting EU cohesion, taking away the political oxygen to deal with other challenges in the economy or Ukraine," she told Reuters in an interview.

Governments could fall over the issue and upcoming elections could be swayed. Already, the rise of anti-immigration populist parties was putting the Nordic social model at risk.

Fordham also saw a possible impact on Britain's negotiations to change its relationship with the EU before it holds a referendum on continued membership by the end of 2017.

"The UK's perceived failure to participate in burden-sharing could further undermine David Cameron's ability to extract concessions ahead of the referendum," she said.

Cameron has refused to join any European scheme to relocate refugees, and insisted the answer was not to take in more people until he bowed to media pressure after an outpouring of emotion over pictures of a drowned Syrian toddler on a Turkish beach.

Peter Kellner, president of the opinion pollster YouGov, said the refugee crisis and British public anxiety about uncontrolled immigration from EU countries made a vote for "Brexit" more likely, though still not the most probable outcome.

"In the public mind they feed a single narrative: that Britain is being swamped by new arrivals and the EU carries much of the blame," Kellner wrote in a comment for Prospect magazine.