Extremist messaging now woven into music and YouTube videos, with one expert saying: ‘You can be radicalised sitting on your couch’

The two men chop peppers, slice aubergines and giggle into the camera as they delve into the art of vegan cooking. Both are wearing ski masks and T-shirts bearing Nazi symbols.

The German videos – titled Balaclava Kitchen – started in 2014 and ran for months before YouTube took down the channel for violating its guidelines.

But it offered a glimpse of how far-right groups have seized on cultural production – from clothing brands to top 40 music – to normalise their ideas, in a process that researchers say has hit new heights in the age of social media.