The German armed forces are to become "the strongest conventional army in Europe," Chancellor Friedrich Merz said as he set the ambitious goal in his first government declaration to the Bundestag this week.

"We must be in a position to defend ourselves so that we do not ever actually need to defend ourselves," said the new head of government, referring to the threat posed by Russia. This is to be achieved in close coordination with European partners, and with the UK, in particular.

This was made official last fall in an agreement that both countries celebrated as "historic." It has become known as the Trinity House Agreement, named after the place in London where it was signed by Defense Minister Boris Pistorius and his British counterpart John Healey last October. Never before has there been such an agreement between the two countries.

Healey traveled to Berlin on May 15 to firm up the joint plans.

Common strategic goals

Although the UK is no longer a member of the European Union, the nuclear power remains a strong military partner in NATO and shares common interests with Germany.

"The UK is deeply involved in the geographical areas that are important to Germany, such as the Baltic states and the far north, but also to some extent on NATO's eastern flank," stressed Ben Schreer, head of the Berlin office of the International Institute for Strategic Studies.

Both countries now intend to join forces to protect the North Atlantic and the North Sea, for example. Not only do important sea trade routes run through the North Sea, but also gas pipelines and cables that carry electricity from large offshore facilities to the coast.

Following suspected Russian attacks on underwater cables in the Baltic Sea, security experts fear similar attacks in the North Sea. Both countries want to work to counter such attacks by providing a "clear and comprehensive picture of the underwater situation," the agreement states.

Joint operations with submarines and maritime reconnaissance aircraft are also part of this plan. In the future, the German P-8A Poseidon maritime patrol aircraft will be deployed from Scotland to help monitor the airspace over the North Atlantic. The Bundeswehr has placed a new order for these aircraft and the British Army is already using them, meaning that German crews can already train there.

"These long-range maritime reconnaissance aircraft can target submarines over long distances," said Defense Minister Pistorius after the discussions with his British counterpart. As a result, both partners will jointly strengthen NATO's submarine-hunting capabilities in the North Atlantic and North Sea.

Development of long-range missiles

Both countries have a strong defense industry, and there are also plans for cooperation in this area. For example, the German armaments group Rheinmetall manufactures the Boxer armored transport vehicle at its plants in the UK, of which the British army has ordered 500 units.

One of the key elements of the agreement is the joint development of precision weapons with a range of more than 2,000 kilometers (about 1,200 miles), which other European countries can also take part in.

Another potential cooperation is the development of armed drones, an area in which the Bundeswehr is lagging behind. The German army only started acquiring smaller combat drones this year. The British Army, on the other hand, has years of operational experience in this field, from which the Bundeswehr could benefit.

Developing compatible weapons systems

The two countries also want to cooperate on developing fighter aircraft for the future — up to a point, at least. That's because Germany is already developing a new system in collaboration with France and Spain, while the UK is developing a different system together with Italy and Japan.

"From a European perspective, it makes perfect sense to at least ensure that the two systems are compatible so that they can work together in future joint missions," said security expert Schreer.

This addresses a point where Europe has repeatedly created obstacles for itself: there are too many different weapons systems, some of which are not compatible with each other. "We need common standards and we need a simplification of systems in Europe," said Chancellor Merz shortly after taking office.

At a time when European NATO states are having to shoulder a greater burden in terms of defense, German-British cooperation could set an example. It is "a constructive building block" that complements other forms of cooperation, said Schreer, like that between Germany and France.

As he sees it, "the big question is what the UK will be willing and able to contribute to the defense of Europe. And this, of course, raises some crucial questions, especially with regard to the UK's defense budget, where larger investments are likely to become increasingly difficult."

How much money will the Bundeswehr get?

In Germany, the question of the size of the future defense budget is also under discussion. Due to the change of government, there is still no budget for 2025, but there has already been heated talk about the required sums.

On Thursday, German Foreign Minister Johann Wadephul, of the conservative CDU, backed the target set by US President Donald Trump of spending up to 5% of gross domestic product (GDP) on defense in the future — and immediately faced backlash from his coalition partners, the center-left Social Democrats.

After his meeting with Healey, Defense Minister Pistorius explained he was responsible for drawing up the defense budget. He said NATO's decisions at its upcoming summit in June will serve as a benchmark.

"We all know that this will be much more expensive than the 2% that is being discussed today," adding that 3% of economic output or more is "not unrealistic."

"It's not just about how much we spend, but how we do it," added British Defense Minister Healey.

This article was originally written in German.

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