Swedish workers are uniting against Tesla. From tomorrow, cleaners will stop cleaning Tesla showrooms, electricians won’t fix the company’s charging points, and dockworkers will refuse to unload Tesla cargo at all Swedish ports. What started as a strike by Tesla mechanics is spreading, in something Swedish unions describe as an existential battle between Elon Musk’s carmaker and the conventions they say make the country’s labor market fair and efficient.

The standoff in Sweden is the biggest union action the company has faced anywhere in the world. Sweden doesn’t have laws that set working conditions, such as a minimum wage. Instead these rules are dictated by collective agreements, a type of contract that defines the benefits employees are entitled to, such as wages and working hours. For five years, industrial workers’ union IF Metall, which represents Tesla mechanics, has been trying to persuade the company to sign a collective agreement. When Tesla refused, the mechanics decided to strike at the end of October. Then they asked fellow Swedish unions to join them.

“Collective agreements form the backbone of the Swedish labor market model,” says Mikael Pettersson, head of negotiations at the electricians’ union, which plans to join the blockade tomorrow. “Fighting for the Swedish model becomes even more crucial when it involves such a large company as Tesla.”