On a wet evening in Suhl, in the former East Germany, a smattering of youthful faces were among hundreds lining up to hear from an unlikely idol - Björn Höcke, one of the most controversial figures in the far-right Alternative for Germany (AfD) party.

The leading candidate, Friedrich Merz, a conservative who has adopted many of the AfD’s hard-line positions on immigration, used his closing statement of the debate to promise his voters that he would never allow the AfD into his government. Under him, he said, the firewall would hold.

Concern is growing over the far-right Alternative for Germany party’s rise ahead of the German election. Its U.S. supporters include Elon Musk and JD Vance.

Alternative for Germany appears to be heading for its strongest national election result yet this month and has become a factor that can’t be ignored.

While polling suggests Germany's far-right AfD party will fare well, it's very unlikely to be part of the next government of Europe's biggest economy.