The German Green Party has been hit by a new scandal after one of its best known and most controversial politicians used the n-word in a tweet. Boris Palmer, the maverick mayor of Tübingen, who only months ago was widely hailed for his successful coronavirus policy, faces expulsion from the party over an alleged racist tweet. The scandal comes at a pivotal moment for the Greens, who are currently leading in the polls ahead of September’s elections. Annalena Baerbock, the party leader, has promised decisive action against Mr Palmer after he used the racial slur in a tweet defending a former German footballer against accusations of racism. “Aogo is a poor racist,” Mr Palmer wrote of Dennis Aogo, the former international. “He offered his n----r d--k to women.” Mr Palmer was defending Mr Aogo, who is of mixed German and Nigerian heritagem,after he was fired from his role as a television pundit over remarks in which he spoke of “training to the point of gassing”. He also spoke out in support of Jens Lehmann, another former footballer who described Mr Aogo as the television network’s “token black”. Mr Palmer has denied the charge of racism and says it should be clear his tweet was “obvious irony taken to the extreme”. He is refusing to resign quietly from the Green Party and insisting on a full hearing.