Tesla sales are falling and apps and online groups are springing up to help consumers choose non-US items

The renowned German classical violinist Christian Tetzlaff was blunt in explaining why he and his quartet have cancelled a summer tour of the US.

“There seems to be a quietness or denial about what’s going on,” Tetzlaff said, describing his horror at the authoritarian polices of Donald Trump and the response of US elites to the country’s growing democratic crisis.

“I feel utter anger. I cannot go on with this feeling inside. I cannot just go and play a tour of beautiful concerts.”

Tetzlaff is not alone in acting on his disquiet. A growing international move to boycott the US is spreading from Scandinavia to Canada to the UK and beyond as consumers turn against US goods.