Bosch is a major player in the auto supply chain. The company said it was looking at defence applications for its products. But “regardless of current developments, Bosch does not develop, manufacture or sell weaponry”.

The cautious tone at Bosch and Volkswagen may reflect a worry that the world isn’t quite ready to see German civilian industry involved in rearmament, which would trigger memories of the Nazi war machine.

But Matthias Wachter, a defence specialist at the German business lobby group BDI, says attitudes have fundamentally changed.

“Ten years ago, big industrial companies tried to get rid of everything which was somehow defence-related. Defence was like porn and cigarettes – nobody wanted to get involved, it looked really bad on your corporate social responsibility reports,” he says.

“Now, really the opposite is the case. It’s about, ‘How can we help? How can we benefit? How can we bring new technologies and innovation into the armed forces?’”

Deutz has embraced the shift wholeheartedly. It is not only selling its own products into defence supply chains, but is now buying, or joining forces with, companies in the drone manufacturing industry.

Schulte says these players have good products, but a company like Deutz can help them scale up production and build out a supply chain. He reckons this is the “blueprint” for how old-school industry can join forces with cutting-edge defence start-ups.

Other companies are looking to do the same. A few weeks ago, defence minister Boris Pistorius and economy minister Katherina met 100 chief executives from defence and non-defence companies to explore deeper collaboration.

Keller says this is unprecedented in Germany. When he worked for the then-defence minister Ursula von der Leyen in the 2010s, “not a single CEO of a defence company was ever seen at the ministry”.

Adapting to the military

But rescuing German industry from the doldrums will require more than just money and enthusiasm.

Not everyone is sure that the government will be able to parlay the budgetary billions into a strategically coherent plan – one that fosters cutting-edge industries like drones and satellites, rather than just grinds out extra artillery shells and armoured vehicles.

Experts also warn that many industrial companies will find it difficult to adapt to the military’s complex procurement processes.

“It is a highly traditional business. The contracts are usually awarded to companies that are well-known and established in the business. So it’s not easy for new companies to break into that,” says Keller.

Wachter agrees: “We always tell our members it’s a long shot, it’s a marathon, and it’s not something which can be easily achieved.”

Even those who do break in may find that their defence business isn’t on the scale of their traditional one.

“In a good year, we are able to produce about 180,000 engines. There’s no way that we’re going to produce 180,000 or even 50,000 or even 30,000 engines for defence applications. We’re talking about a few thousand,” Schulte says.

“It is becoming an important part of the business – in our purpose, the number of employees, the increasing revenue and profitability. But it’s not going to be the dominant part.”

What’s true for the companies is also true for the economy as a whole, says ING’s Brzeski. The automotive industry accounts for as much as 7pc of the German economy, whereas defence contributes just 0.5pc.

“We could see that going to 1pc or 1.5pc this year, but this is not enough to completely absorb weaknesses in the automotive industry,” he says.

If the government plans carefully, the defence billions could be more than just an economic “sugar rush”, Brzeski says, and become a source of longer-term growth based on “more innovation, and more well-paid jobs”.

Pistorius has been working on several strategies and plans to guide the defence sector in this direction. But, like a German train, their release is behind schedule.

Without these, it will be difficult for the bureaucracy, the military and the companies to shift from box-ticking to industry-building.

The industry is gearing up. But Berlin needs a plan to ensure that Germany gets, almost literally, bang for its buck.