But fans of the show discovered at an RTS London event that some of the show’s characters could yet draw new breath.

“The trilogy is over,” confirmed the show’s co-creator Jörg Winger, “but we are currently thinking about a spin-off that is not Deutschland, but maybe follows some of our characters into new territory”.

Walter Iuzzolino chose Deutschland 83 as the launch show for Channel 4’s new foreign drama strand, Walter Presents, in January 2016. Starring Jonas Nay as reluctant spy Martin Rauch, it aired in the week’s most competitive drama slot, Sunday night at 9.

“The [ratings] surprised us beyond our wildest dreams. The programme bagged over 1.5 million viewers live and, with consolidation a week later, 4 million, which made it the highest rating foreign drama ever in the UK. It put Deutschland 83 in a completely different league from even the most successful Scandi noirs we all knew and loved,” said the Walter Presents CCO, who was introducing the London event.

The German thriller became a worldwide hit after being picked up by Amazon for its second (Deutschland 86) and third and final series, Deutschland 89. “[It is] a show that truly changed the telly landscape,” added Iuzzolino.

The final series begins with the fall of the Berlin Wall. “In Germany, you have seen the lead up to the fall of the wall many times,” said Jörg. “For us, the most interesting question was, ‘How do people reinvent themselves when their country and everything around them is falling apart. How do people deal with a crisis of that magnitude.’

“It was far from clear that we were going into an era of unification… People were dreaming of a new socialism, a better socialism. Many, many people were against reunification.”

The Deutschland trilogy has found fans around the world. “The more specific the story, the more universally it can travel, which is counter-intuitive,” argued Anna Winger, the drama’s British-American co-creator and Jörg’s wife.

She offered the Netflix show Unorthodox, which she co-created, as another example. “[It] is in Yiddish, a language that almost nobody speaks, people really connected to it around the world. The same is true with Deutschland.

“It’s fantastic that you can make a niche product… and you can find the other crazy people in the world who are just as interested in it.

“The scaling of niche content that’s possible through global streaming is an amazing thing. It doesn’t change the national experience because you’re still talking to your friends, family and colleagues about something you watched on TV, but it provides this opportunity to have a big conversation with a wider audience, and that’s exciting.”

A programme set in the recent past, explained the executive producers, is just as expensive to make as a “frocks and bonnets” costume drama. “As soon as someone goes outside, you have to change all the cars in the street – it doesn’t matter if it’s 1800 or 1985,” said Anna.

“Since it’s Berlin or Leipzig, you have to change everything because these cities have changed in a way that no other cities in the western world, at least, have changed over the last 30 years,” added Jörg.

The Cologne-born Jörg Winger recalled thinking when the Berlin Wall fell that “this battle between ideologies is over and every country will become a liberal democracy.

“I could never imagine in 1989 that we would see countries putting up walls… [like] the wall between the United States and Mexico. Brexit is a kind of a wall too… [because] it limits free movement.”