Hungarian prime minister Viktor Orban will address German chancellor Angela Merkel’s Bavarian allies at their winter retreat on Friday, a provocative invitation just two days before make-or-break coalition talks in Berlin.

The appearance of Mr Orban, seen as an authoritarian leader in many western European capitals, chimes with a hardening position on immigration and the EU in Bavaria’s Christian Social Union (CSU).

Reeling from a disastrous election last September, the CSU is anxious to boost its traditional conservative profile ahead of a crucial state election next September.

Bundestag deputies meeting until Saturday in Kloster Seeon, a former lakeside monastery near the Austrian border, also want to nail down policy demands before exploratory talks begin on Sunday with the centre-left Social Democratic Party (SPD).

“I will personally do everything I can to make sure this coalition comes together,” said CSU leader Horst Seehofer, the outgoing Bavarian state premier. “This project can work out if the potential coalition partners don’t overreach.”

After final preparatory talks on Wednesday night, the CSU, SPD and Dr Merkel’s Christian Democratic Union (CDU) said they were “optimistic” of reviving their outgoing grand coalition.

‘Rummaging’

But the CSU, anxious not to appear too conciliatory, urged the SPD on Thursday to embrace progressive policy on employment and security rather than “rummaging in the socialist trunk”.

Meanwhile, Alexander Dobrindt, a leading CSU figure, on Thursday argued in Die Welt daily newspaper for a “conservative revolution” in Germany, half a century after the 1968 left-wing student revolution.

“There is a conservative majority in our country, we’re not a left-wing country and left topics must not be allowed dominate,” he said.

His “conservative manifesto” was seen as a play for disillusioned conservative CDU/CSU voters who turned last year to the far-right Alternative für Deutschland (AfD). Ahead of September’s state election election in Bavaria, the CSU has embraced the winning election policies of conservative chancellor Sebastian Kurz in neighbouring Austria.

Like Mr Kurz in his campaign, the CSU is demanding immigration restrictions, cuts to family reunions and to benefits for asylum seekers. In addition it wants to make successful asylum applications dependent on proof of identity and age, a bid to appease Bavarians on the front line of the 2015-16 refugee crisis.

Accession talks

With an eye on the AfD, meanwhile, the CSU has presented a paper strictly opposed to closer European unification and demanding an immediate end to EU accession talks with Turkey.

That in turn opens a door to Friday’s Kloster Seeon guest, Viktor Orban. Though not all CSU politicians are happy with their party’s choice of guest, they are keeping their concerns to themselves.

Mr Seehofer, the CSU leader, warning against German “arrogance” and “smart alecs”, said the invitation was about keeping open communication channels to Budapest,

Though Mr Orban was Dr Merkel’s most energetic opponent in the refugee crisis, Mr Seehofer pointed to long-standing links between the CSU and Mr Orban’s Fidesz party.

Another guest during a Brexit session in Kloster Seeon is the UK business secretary, Greg Clark.