Over the past few months, Europeans have gradually wrapped their heads around the idea that the United Kingdom might actually vote to leave the European Union. Contingency plans were developed to prevent “contagion” and stop the EU unravelling. Yet when Europeans woke up on Friday morning to discover the Brits had actually done it, they, like many of us in the UK itself, were shocked.

In particular, the British decision sent shockwaves through Germany, which finds itself increasingly at the centre of the EU and, as the chancellor, Angela Merkel, said on Friday morning, feels a special responsibility for it. The crisis comes after three others during the last six years, all of which are far from resolved. But Germans see Britain’s decision to leave the EU as an even greater existential threat than the refugee crisis, which had in turn affected them more directly than the euro crisis or the Ukraine crisis.

Merkel graphically described the British vote as an “incision” in the European project. Social Democrat leader Sigmar Gabriel tweeted simply: “Damn. A bad day for Europe.” The cover of the new issue of Spiegel, published on Friday, went even further. It showed the Queen walking over the European flag and declared: “Europe is dead. Long live Europe?”

Germans are astonished and baffled that the British, whom they had always thought of as pragmatic, would put what they see as an imaginary form of sovereignty above clear and hard economic interest. But now it has happened – and they find themselves between a rock and a hard place. Not least because of the importance of the UK as a trading partner, the instinct of many Germans is to do all they can to keep the UK in the single market.

While other European leaders, including European commission president, Jean-Claude Juncker, called for the UK to invoke article 50 of the Lisbon treaty as soon as possible so it could leave quickly, Merkel cautioned against reaching any “simple and quick conclusions” that could divide Europe further.

The reality is that there is little appetite for further integration even in 'core' Europe

At the same time, Germans fear emboldening Eurosceptic forces in other EU member states. The big worry in Berlin is France. A much-quoted recent poll showed the French population was even more Eurosceptic than the British. Front National leader Marine Le Pen is expected to go through to the second round of the presidential election next year and has called for a referendum on French membership of the EU.

For that reason, Germans want to avoid making too many concessions to the UK that would give incentives for other states to follow suit. The finance minister, Wolfgang Schäuble, said earlier this month that “in is in, out is out”, and ruled out the so-called Norwegian model, which would allow the UK access to the single market. A leaked finance ministry paper instead proposed a looser “association agreement”.

But that approach has been criticised by some who argue that it is not in either the German or the European interest to “shut the door” in the UK’s face, as one columnist in the (itself somewhat Eurosceptic) Frankfurter Allgemeine Zeitung, Germany’s newspaper of record, put it. She called for “a fraction of the enormous flexibility that Brussels showed when, at the highest financial risk, it tried to keep Greece in the euro”.

The instinct of many pro-Europeans, in Germany and elsewhere, is also to push forward with further steps in integration among the core around the eurozone to demonstrate the resilience of the EU.

In the weeks leading up to the referendum, there was much speculation about whether the French and German governments might immediately announce a new initiative after the UK had voted to leave, perhaps on European defence.

The reality, however, is that there is little appetite for further integration even in “core” Europe. It was striking that even Schäuble, a federalist who saw “Grexit” as an opportunity because it would be so “traumatic” that it would force further integration, said earlier this month that the EU couldn’t simply react to a British vote to leave the EU with a call for more integration. “Many would rightfully wonder whether we politicians still hadn’t understood,” he told Spiegel.

Thus Europe cannot go forward. Meanwhile, to go backwards goes against the idea of European integration and would be seen as precisely the wrong message to send right after the first major step in European fragmentation. And the status quo is unsustainable. Thus, Europe is, as the German political scientist Claus Offe has written, entrapped.

The fear, though, is that the British decision to quit the EU has set in motion a dynamic of disintegration that cannot be stopped. So-called functionalist theorists of European integration believed that it would be a kind of self-perpetuating process, whereby steps in one area would lead inexorably to steps in other areas – what they called “spillovers”.

Now the same thing might happen in reverse: “spillback”.

Hans Kundnani is the author of The Paradox of German Power