Adolescence has dominated the UK’s national conversation over the last few days – the prime minister even referenced it in parliament – and this week it is the most-streamed Netflix show in the US. However, as well as its content, there is also widespread fascination about its technical mastery. Each of its four hour-long episodes was captured in a single take, which required meticulous planning and endless innovations on the part of its crew.

Many of the details are already out there, in a series of social media threads that went viral this week. However, last month I interviewed the key creatives of Adolescence, and they provided me with several backstage stories that I had to leave out because of a lack of space or because I didn’t want to spoil their head-spinning impact. With that in mind, here are a few leftover secrets from my conversations about Adolescence.

It all began as a favour for a mate

Before Adolescence, there was Boiling Point, a one-take movie starring Stephen Graham and directed by Philip Barantini. “This was how the whole thing started,” recalled Graham. “Phil said he wanted to be a director. And I was like: ‘OK.’ And then he said: ‘Will you be in my first film?’ And I said: ‘No. Go and show me what you can do. If it’s any good, we’ll have a talk about another one.’” Barantini did just that, and his second idea was the short that became Boiling Point. “I made that short film as a favour for a mate,” Graham said. “So you never know what can happen.”

Its young star is mad about swingball

Given the subject matter, production took a lot of care to protect the show’s young star, Owen Cooper. “We had lots and lots of comfort blankets around him,” said Barantini. “There was a child psychologist on set every day and chaperones. He was very, very well looked after. But I think we were more concerned for him than he was. At the end of each take, it’s emotional, and everyone’s gone through this huge rollercoaster, and I’d be like: ‘Owen, are you OK?’ Then he’d be like: ‘Yeah, I’ve got a swingball game to play with my chaperone. Am I good to go?’” In a separate conversation, the show’s writer, Jack Thorne, said: “All he wanted to do was play swingball.”

If you look closely, you’ll see the camera operator at one point

In the final moments of episode two, there is an incredible shot where the camera magically takes off and flies through the sky before landing next to Graham. Here is how Barantini described it: “As Ashley [Walters, as DI Bascombe] leaves in his car, we have a team coming up behind Matt [the cinematographer, Matthew Lewis], who clip the camera to a drone with a hook. Then we fly the drone over the town. In the meantime, Matt legs it into a van. He drives to the end site, catches the drone with two other people, disconnects it and starts walking towards Stephen’s face.” Lewis’s journey had to be split-second accurate and, as Barantini revealed: “If you watch it again, you’ll see his van drive into the car park as the drone comes in to land.”

That incredible drone shot was nearly very different …

“The original idea was that the drone would just take off, fly over the murder site, and then keep flying,” said Barantini. “That was supposed to be the end of the episode. But then on Wednesday of the shoot week, Toby Bentley, the Netflix executive, said: ‘Wouldn’t it be great if we could have Stephen at the end?’”

… and it almost didn’t happen at all

Filming for each episode took place over a week. “We’d do a take in the morning and a take in the afternoon every day,” said Graham. “On Wednesday, Toby had his idea. It was like: ‘Shit, that only gives us Thursday and Friday to get it right.’ On Thursday, the winds were too high. Friday morning, the winds were OK, but the drone wobbled and fell.” A plan B was hatched to ditch the drone altogether and end on a shot of Graham standing by the school where the bulk of the episode took place. “Friday afternoon was our final chance,” continued Graham. “It’s the last take. Let’s see what happens. Everyone’s on the same page. We’re all locked in. Away it goes. And the final take of all is the take that you see.”

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The locations were meticulously researched

Boiling Point was written in the film’s sole location, a restaurant, so Barantini could figure out the camera moves as he worked on the script. But Adolescence has far more moving parts, and worked across multiple locations each episode. “Matt and I would have the map of the area, then plan it from there,” said Barantini. “Before we had any actors come on set, we would have mapped out the whole episode with the cameras.”

The bulk of the first episode takes place in a police station. However, this was a set. “We found a location for the station in Pontefract,” said Barantini. But the house that was raided before the arrest was a real house. “So we had to find a house a three-minute drive from the studio. It was quite a lot of planning.”

Cooper’s voice almost gave out in episode three

The third episode – the two-hander between Cooper and Erin Doherty as his child psychologist – was the first of the series to be shot; a daunting task given that it was also Cooper’s first acting job. Again, multiple takes were filmed. “The one they used was the one where Owen had a bad cough,” said Doherty. “But Phil loved it.” Cooper said: “I was screaming and shouting in every take, twice a day. So you know, my throat was going all crazy. By the final take, I sounded like I’d been smoking for about 30 years.”

Adolescence is on Netflix now