A 19th-century slogan is getting a 21st-century makeover. The workers of the world really are uniting. At least, some of them are.

The economic meltdown unleashed by the 2008 financial crisis hit southern Europe especially hard, sending manufacturing output plunging and unemployment soaring. Countless factories shut their gates. But some workers at perhaps as many as 500 sites across the continent – a majority in Spain, but also in France, Italy, Greece, and Turkey – have refused to accept the corporate kiss of death.

By negotiation, or sometimes by occupation, they have taken production into their own hands, embracing a movement that has thrived for several years in Argentina.

In France, an average of 30 mostly small companies a year, from phone repair firms to ice-cream makers, have become workers’ co-operatives since 2010. Coceta, a co-operative umbrella group in Spain, reckons that in 2013 alone some 75 Spanish companies were taken over by their former employees – roughly half the total in the whole of Europe.

A gathering in Marseille last year of representatives from worker-controlled factories drew more than 200 delegates from more than a dozen countries – including pioneers from Argentina, whose turn-of-the-century economic crash sparked a wave of fabricas recuperadas that today has left around 15,000 workers in charge at more than 300 workplaces. The fast-developing phenomenon is now a field of academic study; there are websites, such as workerscontrol.net and autogestion.coop, dedicated to it.

No two self-managed ventures launch in the same circumstances, and many face daunting obstacles: bureaucratic inertia and administrative red tape that can delay or even prevent production; legal opposition from former owners; a still-chilly economic climate; outdated machinery, or products no longer in demand. Lifelong union militants can find themselves, for the first time in their lives, making tough commercial decisions.

But many – for the time being at least – are making it work.