German grandmothers protested outside the offices of state broadcaster WDR in Cologne on Saturday after the station posted a satirical video about old people’s environmental carelessness.

The demonstrations, which police estimate attracted more than 1,000 protesters and counter protesters, follow several days of death threats against prominent journalists from the German network who have spoken out in support of the video.

On Saturday a man, who was later found to be carrying a knife, was arrested for attacking counter protesters, while on Sunday five members of far-Right groups were detained after climbing onto the roof of the WDR building.

The video, which is set to the tune of a well-known children’s song, satirises older generations’ attitude to the environment and climate change, including the provocative refrain “my grandma is an environmental pig”.