US UNION the United Auto Workers (UAW) has called on the country’s National Labour Relations Board (NLRB) to annul the result of last week’s failed recognition ballot at an Alabama Mercedes-Benz plant.

It wants the NLRB to order a new election, citing illegal anti-union activity by the German car manufacturer ahead of the vote, in which 56 per cent of workers voted against unionisation.

“Over 2,000 Mercedes workers voted yes to win their union after an unprecedented, illegal anti-union campaign waged against them by their employer. What that tells us is that in a fair fight, where Mercedes is held accountable to following the law, workers will win their union,” UAW says.

It accuses Mercedes-Benz of firing four pro-union workers and allowing anti-union workers to lobby colleagues on company time, while denying that right to union supporters.

The NLRB confirmed it has received the request and is reviewing it. It is also investigating six other unfair labour practice charges filed by the union since March, including that Mercedes disciplined workers for talking about unionisation at work and prevented distribution of union materials.

The company is also now officially under investigation for anti-union conduct at the Alabama plant by Germany’s Federal Office for Economic Affairs and Export Control.

Many German manufacturers have been shifting production to the United States, as sanctions on Russia force up the price of energy in Europe and President Joe Biden’s Inflation Reduction Act provides attractive subsidies which have prompted EU complaints.

German firms announced a record $15.7 billion (£12.3bn) of capital commitments in US projects last year, nearly double the $8.2bn (£6.4bn) of just a year earlier, according to analysis by the Financial Times. Mercedes was responsible for the second-biggest of all such investments after Volkswagen.

Manufacturing output in Germany has in contrast dropped two years in a row and is now nearly 10 per cent down on 2018 figures. Germany’s economy is projected to shrink by 0.5 per cent this year, with analysts saying the country faces its most serious slump in two decades.

Mercedes’ behaviour in Alabama could suggest German firms hope to exploit the US’s weaker trade union rights as they increasingly shift operations offshore.