Angela Merkel has gone out of her way to woo British citizens to vote to remain in the European Union. Everyone in Germany is keen to avoid a "Brexit" - as the UK is seen as a crucial ally.
German politicians have long refused to be drawn into the Brexit debate. They fear that whatever they say would give a boost to the "Leave" campaign.
But now that opinion polls indicate that the Brexit campaign may actually be getting the upper hand, there is a growing sense of panic in Berlin.
The German government is wishing more than anything for Britain to stay in the EU.
Earlier this month, Deputy Chancellor Sigmar Gabriel warned of "dramatic" political and economic repercussions for both sides should the UK leave the EU. Chancellor Angela Merkel adopted a more personal approach, saying, "I personally would like to see the United Kingdom stay part of the European Union."
David McAllister, European parliamentarian and member of Merkel's CDU, has dual British-German nationality. In an interview with Deutsche Welle, he said: "A European Union without the United Kingdom would surely not be a better EU. The Brits are traditionally a driving force in promoting the single European market and free trade. They have excellent diplomats and a strong military. There are plenty of good reasons to want to keep them in the EU."
A majority of Germans also wants Britain to remain. DW conducted a poll on the matter in April and a resounding 78 per cent of Germans voted against a Brexit - the highest figure in all five EU countries polled, including Britain itself.
Britain's ruling conservatives are split on the matter, but many Tory politicians sympathize with Angela Merkel and Germany's position on EU membership.
Martin Callanan, former head of the conservative group in the European parliament and current member of the House of Lords, told DW in an interview: "Merkel and Cameron see eye to eye on a number of important issues: on economic policies, free market and fiscal discipline. Those are areas where the British and German conservatives have a lot in common."
Callanan sees a "natural alliance." He believes that Germany and the UK "will develop into the joint leaders of northern Europe, while France will find its role as the leader of southern Europe."
France, with its interventionist policies, and Germany, with its competitive economic approach, may be geographical neighbors, said Callanan, "but they are by no means ideologically close anymore."
Cameron and Merkel have been demonstrating their special relationship: The German chancellor and her husband accepted an invitation to the British Prime Minister's residence in Chequers and in return welcomed Cameron for a weekend in the German government's guest house in Meseberg. Neither Merkel nor Cameron have demonstrated a similar closeness to French President Francois Hollande, although France is often referred to as Germany's closest partner in Europe.
Refugee crisis - a turning point
But all that was before the influx of refugees in 2015 posed a new challenge to Europe. Cameron and Merkel were diametrically opposed in their approach. This destroyed much of the common ground. While Merkel advocated an open-door policy and posed for photographs with grateful refugees in Germany, Cameron categorically refused to allow desperate refugees to cross the channel from Calais in France.
Immigration is also a pivotal topic in the Brexit discussion. The "Leave" camp has repeatedly pointed to Merkel's refugee policy as a dangerous example. "Many Brits believe that the Germans have lost their mind," said British historian Anthon Glees in an interview with German public radio Deutschlandfunk in late 2015 in reference to the German displays of solidarity.
Should Britain opt to exit the EU, Merkel's handling of the refugee situation would surely be one of the reasons prompting that move.
There is one thing pundits on both sides of the channel agree on: Should Brexit really happen, the economic fallout for Britain would be dramatic.
But how much would Germany and the EU really suffer?
Michael Kunert, head of the German pollster infratest-dimap, says the real reason why so many Germans are keen for Britain to stay is simply that "Brexit could be the first step towards a complete disintegration of the EU."
Germany needs a partner to promote economic and financial stability in Europe. If it were to lose its ally Britain, the "southern" European approach would gain the upper hand," says Guntram Wolff, Director of the Brussels-based think tank Bruegel.
He says the politicians in Berlin fear a scenario where Germany would be "left alone" with the Mediterranean countries, who are happy to brush aside budgetary discipline.
There would be more pressure to funnel money into the ailing economies in the south, and Germany would be forced to foot the bill. "That is the big fear," Wolff says.