I first met August Hanning in 2019, but I might have bumped into him 30 years before. He was head of counterespionage for the West German government inside East Berlin. I was a young correspondent there, shortly before the wall came down.

Hanning was a well-known figure, gangly, genial. I’ve met various intelligence folk in my time, and he was more approachable than most. I last saw him less than a month ago at a reception at the British Embassy in Berlin for a German-British-French gathering of the great and good called the Club of Three. He was on the steering committee. We chatted briefly about my most recent book and the (worrying) state of German politics.

He had previously been in a spot of bother but seemed to have emerged unscathed – or at least he gave that impression. The case was bizarre in the extreme.

Christina Block, the scion of a wealthy German family whose father Eugen had established a popular restaurant chain called Block House, had been embroiled in a custody dispute over two of her four children since 2018. A security company was hired to abduct the two children from her ex-husband’s home in Denmark and take them to Germany. Several prominent people were charged in the case, including Hanning, who by now had his own consultancy firm. Hanning denies involvement.

German news media have reported that Hanning, 80, has struggled financially in recent years. He appears to have invested considerable sums in a Latvian bank in 2019, on whose advisory board he sat. The bank went into insolvency, and administrators have been trying to get some of the money back from him and other prominent figures.

It now transpires that during the search of Hanning’s office on the Block case, investigators found documents they believe implicate him in a much wider espionage net.

The charges are the most serious levelled at any major German figure since the 1970s. As head of the BND, the country’s external espionage agency and equivalent of MI6, between 1998 and 2005, he is accused of conspiring to commit treason by sharing highly classified information with a foreign intelligence service. Reports say that could have been Azerbaijan. Links with Russia have so far not emerged.

According to the broadcasters NDR and SWR and the Munich-based newspaper , Hanning is alleged to have paid bribes to his former chief of staff who subsequently served as the BND’s office manager until last March, in exchange for as many as 2,000 highly secret documents between 2010 and June 2022. Some of them may have been used to compile commercial briefings for clients, including foreign governments. “The defendant Hanning was to be able to profitably exploit this information as part of his private consulting work, which he had since taken up,” prosecutors said.

The former manager, identified as Manfred D (German law precludes the use of surnames of people on trial), was also arrested. He faces charges of aiding and abetting attempted treason and aiding and abetting espionage against the state.

This is the latest of several incidents involving German intelligence services. In 2022, a former department head, Carsten L, was arrested and he is now on trial in Berlin on charges of leaking top-secret information to Russia on the BND’s cyber operations – which he denies.

The biggest scandal involved a personal assistant to the then-chancellor, Willy Brandt, in the 1970s. The discovery that Günther Guillaume had been a Stasi agent throughout his time in the top echelons in the West German government brought down Brandt and shone a light on the espionage activities of the Soviet Union and the GDR.

Even after the fall of Communism, other Western countries have suspected continued penetration of Germany security services by hostile actors, particularly Russia and China. Germany is not part of the Five Eyes alliance – the US, UK, Australia, New Zealand and Canada.

And yet, as participants at a recent security forum I attended in Helsinki suggested, that tells only part of the story. Such are the suspicions of the motives and reliability of Donald Trump and the people around him that the Brits and others are similarly wary of giving much away. Given the closeness of the Maga movement to the Kremlin, and the President’s seeming affection for Vladimir Putin, who knows what ends up where?

Trump’s belligerence towards his northern neighbour has led Canadian officials to wonder whether the US administration is an unreliable ally or adversary. The feeling seems mutual. As for the so-called Special Relationship, Trump is going out of his way to express his displeasure towards Britain and apparently to exact revenge. It might well be that he speaks before he thinks, but why else would he all but endorse Argentina’s claim to the Falkland Islands and embrace the idea of a united Ireland?

These are security issues as much as they are political. Then there are the extraordinarily murky events around RAF Fairford and the panicked withdrawal of US bombers from the base. The true story around the men arrested and bailed and suggestions of an Iranian threat has yet to come out and it is too early to draw definitive conclusions.

What seems clear, however, is that trust and cooperation are not what they used to be. Countries that used to form a united West now seem to ask with increased regularity of each other: whose side are you really on? Some intelligence failures revolve around avarice; others around treachery; others around a change of course. The first two, perilous though they are, have been with us for decades. What’s new is the bigger question of allegiance.

John Kampfner is author of Braver New World