The solution to Europe’s challenges? More Europe, according to Manuel Valls, Prime Minister of France. As leaders gathered in Davos to discuss the future of the EU against a fraught political and economic backdrop, Valls made a plea for solidarity.

“History is at a moment of convergence, he said. "All the parameters mentioned at the beginning (of the session) – Ukraine, terrorism, the refugee crisis, separatism – nothing could be worse than to see a member state leave, as it would be a signal to others and pave the way for more populism. We need more Europe.”

With Britain facing a public referendum on EU membership by 2017, he added:

In a special address, Britain’s Prime Minister David Cameron struck a less effusive note, though he said he wanted to “go out and campaign for Britain to stay in a reformed Europe”.

He outlined four priorities for reform – competitiveness, flexibility on membership of the euro, sovereignty, and control over migration and welfare – while making it clear that he opposed ever-closer political union.

Meanwhile, Greek Prime Minister Alexis Tsipras voiced support for a future within the European Union, echoing France’s Manuel Valls. "In order for us to find a solution to the problems of Europe, we need more Europe," he said. "This is not the right time to talk about exits – be they Brexit or Grexit. No more differentiation; now is the time for solidarity."

Prime Minister Tsipras also drew attention to the ongoing humanitarian tragedy on his country’s shore, with “people losing their lives in the sea because traffickers are working there unimpeded.”

He called for a mechanism to help relocate refugees throughout the rest of Europe, in all EU states.

Germany’s finance minister, Wolfgang Schäuble, said there was a need to stem the flow of refugees into Europe in the first place, by investing “billions into those regions from which the refugees come”.

He also addressed the broader challenges of Europe’s long-term economic future, saying: "Because of the speed of global change and the effects of the Fourth Industrial Revolution, we have to help EU states become as competitive as possible.”

As the IMF released a report on the economic impact of Europe’s refugee crisis, Christine Lagarde told journalists at Davos that the influx of new arrivals, if integrated into labour markets, would ultimately have a “positive, but small” impact on the bloc’s GDP.

The Annual Meeting is taking place in Davos from 20 to 23 January, under the theme “Mastering the Fourth Industrial Revolution”.