A European Union flag is seen in front of the Parthenon temple in Athens
EIU says there is a 60% chance of Greece leaving the EU before 2020Reuters

The European Union is facing a myriad of risks and challenges that could tip it over the edge as early as this summer, according to the Economic Intelligence Unit (EIU). The research firm says Britain's potential exit, Greece's debt problems and the migration crisis could all come to a head to overwhelm policymakers in the 28-member state bloc.

However, it does not expect Britons to vote to leave the EU in the 23 June referendum, despite the Vote Stay campaign suffering recent setbacks. A "botched budget", the resignation of Iain Duncan Smith and a "fumbled response" to the Panama Papers leak are all seen to have contributed to the momentum shifting towards the Leave campaign.

"Policymakers appear increasingly unable to understand and respond to the desires of their electorates. This is leading to voting patterns that could have lasting destabilising effects," said Aengus Collins, country forecast director at EIU.

"Nowhere are people more jittery about electoral risk right now than in the UK. We're sticking with our years-old forecast that in June the UK will vote to remain in the EU — the pull of the status quo will strengthen as the vote draws closer and the risks of Brexit crystallise — but all the momentum has been with the Leave campaign in recent weeks and nothing can be taken for granted."

Migration woes

The EIU puts the migrant crisis as a "graver risk" to Europe than the financial and economic crisis that preceded it. European leaders struck a controversial deal with Turkey in March to send back any refugees and migrants who fail in their asylum claims.

But the plan is wrought with enormous legal challenges, with the European Convention on Human Rights prohibiting the mass expulsion of foreigners. "If [the EU-Turkey deal] collapses, we are back at square one and facing a crisis with the potential to pull the EU apart," the report said.

Idomeni, Greece
Europe is grappling with its worst refugee crisis since World War IIReuters

Greece's continuing sovereign debt crisis is another area of concern. The research firm estimates there is a 60% chance the country would have left the EU by 2020. "It is questionable whether any Greek government, of any political complexion, could implement the measures required under the third bail-out programme," it said.

"A Grexit would represent a huge political failure for the bloc, with potentially destabilising consequences: the principle of irreversibility would have been shattered."

The EIU believes Europe can "muddle through" individual crisis — at a significant political and economic cost — but is at risk of being overwhelmed by multiple crises coming to a head simultaneously.

"This could happen as soon as mid-2016, when the UK votes on whether or not to remain in the EU, Greece has large debt payments falling due and this year's migrant influx is likely to peak," it warned.