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.

On Sunday, the country’s residents will vote in a pivotal election in which Ms Weidel's party, Alternative for Germany (AfD), is tipped to come in second. A snap election was called at the end of last year by current Chancellor Olaf Scholz, of the Social Democratic Party (SPD), when his coalition Government fell apart.

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.

Germans will head to the polls Sunday looking for leadership at a deeply uncertain time, but all eyes will be trained on a party likely to finish a distant second.

The leader of the Alternative for Germany (AfD) party has been endorsed by Donald Trump - and looks set to make huge gains in this weekend's snap election.