In September, bus driver Andrew Worth climbed onto the stage at the TUC Congress, the annual get-together for Britain’s trade unionists. It was the 150th gathering — a testament to the longevity of a movement that was forged in the industrial revolution. But Worth was less concerned with the past than with the future.

Transport company Stagecoach was starting to trial driverless buses, he told the audience. “My role as a bus driver will in effect be over. I wouldn’t have ultimate control of the vehicle, instead I’d be there as emergency-stop button-pusher. Do you think my company would pay me the same rate of pay? Of course not.”

Automation is a hot topic among trade unions — and with good reason. A slew of economic studies predict that new advances in robotics and artificial intelligence will automate or change a significant number of jobs in the next few decades. Their forecasts vary wildly on how large the impact might be. But it is impossible to ignore the changes that unionists are already beginning to see on the shop floor. “There’s going to be a battle . . . of who ultimately benefits: the bosses or the workers,” one unionist warned at this year’s TUC Congress.

But automation could also be a moment of opportunity for unions. After decades of declining membership across the developed world it could be a chance to win new victories for workers and demonstrate the value of unions to the next generation.

Automation is not a new challenge for the union movement. It was also a big topic at the TUC Congress of 1956, where people were talking about a new “electronic computer” developed by the food manufacturer Lyons. The computer could work out the payslips for 10,000 employees in four hours — a job that used to require 37 clerks.

In a pamphlet published in 1956, the TUC took a decidedly optimistic approach. “Automation offers the prospect of higher pay, greater leisure, and healthier and less strenuous work,” it said, but argued unions would need to make sure the benefits of greater productivity were shared with workers.

These prescriptions from 1956 are remarkably similar to the ones many unions are proposing in 2018. “As new tech grows, everyone should get richer,” Frances O’Grady, the TUC’s general secretary, said in her speech to Congress this year. “Now, as ever, we demand fair shares. That means higher wages. Less time at work. More time with our loved ones. In the 19th century, unions campaigned for an eight-hour day. In the 20th century, we won the right to a two-day weekend and paid holidays. So, for the 21st century, let’s lift our ambition again. I believe that in this century, we can win a four-day working week, with decent pay for everyone.”

In Germany, the industrial union IG Metall is already using its power to translate productivity gains from technology into shorter hours of work for the German workforce. Earlier this year, it struck a landmark agreement with the Südwestmetall employers’ federation which gave workers the right to move from a 35- to a 28-hour week, while preserving the right to return to longer hours. IG Metall’s chairman called it “a milestone on the path to a modern, self-determined world of work.”

“We cannot uninvent new technology, but we can determine how it’s introduced, and who it stands to benefit.”

Trade unions from many different countries are also studying the Swedish approach to displaced workers. Sweden has “job security councils” run by employers and trade unions, which give intensive support and retraining to people as soon as they learn they are to be laid off. The system seems to work: about 90 per cent of displaced workers in Sweden are re-employed within a year, compared with about 30 per cent in France and Portugal, according to OECD data. Swedish employers (which fund the job security councils) say the system is worthwhile because it means workers and unions are less resistant to necessary lay-offs, which allows the economy to evolve more smoothly over time.

Unions with high membership rates and constructive partnerships with employers — like those in the Nordic countries — are the most confident of securing the benefits of automation for workers. “The Nordic unions are like ‘automation, great, bring it on’,” said one economist who met recently with a large number of unions. “But the French had a much darker view.”

Unions whose membership levels are depleted face a bigger task, since they will need to win new members in unfamiliar sectors and hold onto them, even if they are displaced from one workplace to another. Some unions have struggled with this in the past: as automation shrank the size of the UK manufacturing workforce in the decades after 1956, for example, unions failed to replicate their membership levels in the new and growing service sectors.

But the threat — and promise — of automation might prove a good recruiting tool. As bus driver Andrew Worth said: “We cannot uninvent new technology, but we can determine how it’s introduced, and who it stands to benefit.”

Sarah O’Connor is an FT investigative reporter