Angela Merkel and David Cameron could today suffer a joint humiliation in Brussels. Conservative-minded Eurosceptics from Germany and Britain may decide, in defiance of the Chancellor and the Prime Minister, to help form the third largest group in the European Parliament. They and their allies have a good chance of becoming the official opposition to the insatiable federalists whose current front man is Jean-Claude Juncker, a functionary who after 19 years as Prime Minister of Luxembourg is now attempting, with Merkel’s support, to become President of the European Commission.

As with most transactions in Brussels, the details of the possible Anglo-German alliance are at once opaque, complicated and rather dull. So before touching on those, I would like to sketch the wider picture, which has the merit (in my opinion) of being clear, simple and rather interesting.

The basis for an Anglo-German alliance has long existed. While living in Germany in the 1990s, I could not help being struck by the close affinities between British and German public opinion. In either country, you could go into any bar and be sure to find the general feeling was in favour of keeping the national currency. This was part of a wider sense that it was, generally speaking, preferable to run one’s own affairs, for one was likely to make a better job of it than a curious bureaucracy housed in a succession of ever more gigantic buildings in the capital of Belgium.

Post-war German statesmen have often recognised the desirability of forming an alliance with Britain. Konrad Adenauer said he did not wish to be left alone with the more or less hysterical French. But Germany’s political class found it difficult to express the German people’s instinctive attachment to the idea of national sovereignty. Even after the Fall of the Berlin Wall in 1989, and German reunification, the political class remained obsessed by the pursuit of European policies for which no popular mandate had been sought, or would have been given. The German mark, proud symbol of Germany’s postwar recovery, was traded in for the single European currency.

Learned German professors warned Helmut Kohl that the euro would not work. I used to read their agonised protests in the Frankfurter Allgemeine Zeitung. Kohl ignored the professors, drove through the single currency and has left his successors with the unenviable task of preserving it.

But the professors have not gone away. They have observed with horror the grievous damage being done by the euro to the European Union. At the beginning of last year, they set up a new party, Alternative für Deutschland (AfD), dedicated to saving the EU by dismantling the euro.

In last September’s general election, the new party got 4.7 per cent, just short of the five per cent threshold which must be cleared in order to get parliamentary seats. I erred in expecting it to clear this threshold.

In the European elections which have just taken place, AfD advanced to seven per cent of the vote, which means it now has seven MEPs. The party’s admirable manifesto for the European elections opens with these words:

The Alternative für Deutschland (AfD) aims for a European Union (EU) of sovereign states. It rejects a European federal state on the model of the United States of America, because there is no European nation as such and no single European constitutive populace.

The seven AfD MEPs have applied to join the Alliance of European Conservatives and Reformists (ECR) group in the European Parliament, which was founded at David Cameron’s behest in 2009.

One might have expected Cameron would be pleased by these new recruits. His difficulty is that the ECR was set up so he could fulfil his pledge, made during his campaign for the Tory leadership in 2005, that Conservative MEPs would leave the openly federalist European People’s Party (EPP).

Merkel’s Christian Democrats belong to the EPP, and she was profoundly displeased when Cameron took the British Conservatives out of it. Relations between the two leaders took several years to recover.

Cameron has no desire to incur once more Merkel’s displeasure by admitting her enemies, AfD, to the ECR. For his hopes of reforming the EU rest on his alliance with Merkel.

The question of whether or not AfD is admitted to the group does not, however, rest with Cameron. It will be decided by a simple vote of the 46 existing members. Nineteen of those belong to Poland’s Law and Justice party, and are said to favour AfD. Another 19 belong to the British Conservative Party, and most of them are said to favour AfD too. Five of them – Nirj Deva, Julie Girling, Ashley Fox, Daniel Hannan and David Campbell Bannerman – have tweeted their support for AfD. A Czech member of ECR has likewise declared his support for AfD. All these MEPs have been elected to serve for the next five years, which is longer than either Merkel or Cameron may be in office.

The two leaders will need to engage in some pretty ferocious arm-twisting if they are to prevent AfD from joining the ECR. It also looks as if Danes, Finns and Flemish nationalists may be among the others who join the group.

I cannot pretend to a comprehensive knowledge of the horse-trading now going on in Brussels as the various groups in the European Parliament compete for members. People who know a great deal more than I do still become reticent when asked to predict what will happen. It is very difficult to know how much influence Merkel and Cameron will be able to bring to bear.

But I cannot see anything to object to in the statement made to Saturday’s Financial Times by Bernd Lucke, the professor of macroeconomics who leads AfD and is one of its MEPs:

It seems that Angela Merkel tried to mobilise David Cameron to solve her domestic political problems and isolate the AfD. I can’t imagine a British prime minister would allow himself to be manipulated in this way. We have agreement on David Cameron’s agenda for Europe. We support his views on a more decentralised EU. We are exactly the right guys to support his views in Germany. The CDU doesn’t support his ideas. We have the same policies as David Cameron. I think he is being used.

From Cameron’s point of view, one would have thought the admission of AfD would at least have the merit of easing his relations with British Conservative Eurosceptics.

But the situation is certainly very awkward for Merkel. Her Christian Democrats created the room for this anti-euro party, and have failed either to confront or to discredit AfD since it was set up. There is now a battle going on within the Christian Democratic Union (CDU) about how to deal with this upstart.

Merkel herself, and people such as Volker Kauder, who chairs the CDU parliamentary group, continue to hope they can just ignore AfD and it will go away. Kauder has said he will not take part in any talk shows where he has to debate against AfD members: a stand which is pretty rich when one considers that CDU members very often debate against members of the Left Party, heirs to the old East German communists.

Other members of the CDU such as Annegret Kramp-Karrenbauer, Prime Minister of Saarland, and Stanislaw Tillich, Prime Minister of Saxony, favour taking the offensive against the AfD and tarring them as right-wing populists. A minority of conservative CDU members (yes, there are still a few) wish instead to open the party to coalitions with the AfD.

None of these approaches has worked. The AfD attracts a wide variety of protest voters, but its leaders are solidly respectable: they want nothing to do with parties such as UKIP.

And at the end of August, there will be regional elections in Saxony, where AfD got ten per cent in the European elections. Unless something goes badly wrong, the party has every prospect of entrenching its position within German politics. In the post-Merkel era which will open within the next few years, AfD could well replace the Free Democratic Party (FDP), the stricken German liberals, as a coalition partner for the CDU.

Germany has an exceptionally large number of neighbours: it has land frontiers with nine different countries, and is only separated by narrow seas from half a dozen more. It needs some system of co-operation with those neighbours. But as AfD’s professors have spotted, this need not mean the destruction of national sovereignty. Britain ought in the end to be able to make common cause with Germany, to create an EU whose democratic legitimacy springs from national parliaments.