In the hands of Claire Foy the young Elizabeth (“Peter Morgan’s Elizabeth,” Foy notes) is a model of decorum, one who has been brought up well, taught etiquette and propriety, all in the knowledge that she is going to be queen one day. The flip side is that the human part of her character has been overlooked. “She’s not streetwise at all,” says Foy, “and doesn’t have much involvement with the outside world. So she’s very strong and grounded, but she’s also completely naïve to the way the world works and people’s agendas.”

The sudden death of her father George VI and her subsequent ascension to the throne, however, “puts her natural character into a complete state of flux,” and that’s where Morgan finds the drama in the opening episodes of Season 1.

For her performance, Foy chose to cleave to what she saw as that “natural character.” “Although her behavior’s so well documented publicly, you have to take it all with a pinch of salt and realize that we’re not doing a documentary, it’s a fictional program,” says Foy. “You’ve got to let it go and play it in that moment, and hope that means that it’s true.”

“Ultimately,” she adds, “I think she’s a very kind, loving, determined, funny, clever person. Sometimes she’s allowed to show it and sometimes she’s not.” Foy points to an episode in Season 2 as a key scene for her understanding of the character. The queen, unexpectedly, decides she will dance with the Ghanaian President Kwame Nkrumah. “It’s easy to think that Elizabeth doesn’t make any mistakes or isn’t spontaneous. She is a very held person and she is a very in-control person but at the same time, she is prone to jealousy or wanting to break out of the system as much as everybody else. Choosing to dance with Nkrumah is a sign that she is capable of making some very interesting choices. And it was an incredibly brave, bold thing to do at the time.”

And does so with a smile on her face: In a theme picked up by the actors who followed her, Foy stresses the importance of humor in The Crown. “Peter’s [Morgan] incredibly witty, he doesn’t take it too seriously, which is a real attribute. He likes the character to have fun. There’s nothing worse than watching something where no one ever smiles, but with this, there’s so much humor.”

When Olivia Colman took up the mantle for Seasons 3 and 4, she approached it with her own, typical humor. Assiduous research? “Well, [The Crown’s research team] send you everything that’s ever been onscreen, everything that’s ever been written. So you can just sit on your arse and it all comes to you. There’s the voice department team who also are amazing. So, it’s kind of given to you on a plate!”

Colman’s performance, of course, belies her suggestion that she just turned up and gave it a go. She too looked to explore the fissure between how the queen knows she has to behave and what she is feeling inside, particularly in her relationship with her eldest son Charles. “I think that the queen wants to protect him but at the same time needs him to realize, ‘You’re going to be next and you have to do all this, I’m really sorry.’ And there’s some friction, as there would be: I mean, you show me a mother and young adult who are fine with everything.”

Across Colman’s two seasons in the role, she says she saw the queen as both unchangeable (“She’s a rock; immovable”) and yet by turns more understanding and appreciative of human frailty, including her own. “She’s still learning — every human, hopefully, they should still be learning. She’s learning in this different social climate and she’s trying to work out where her monarchy is placed and how everyone feels about it.”

Colman says it was the queen’s self-containment that she found hardest to play: the life of the monarch is one of continual prudence. “Whenever there was a scene where the queen got angry or shouted, I was so excited because I spent so much of the time being very well-behaved. It is the complete opposite of me, so it was actually the hardest part of the job for me, to try and be a little more dignified. And not grin so much. I grin all the time, which I didn’t realize I did until I was told not to.”

As with Foy, Colman stresses the importance of the crew around her as a facilitator of her performance. “I have to say I have loved every second of it and it will be one of the most beautiful experiences of my working life but that’s because of the people: you’re totally spoiled doing this. Everyone was brilliant at their job and made your life really easy.”

When Imelda Staunton came to the role she had the additional pressure of Foy and Colman’s much-lauded portrayals already committed to film. In addition, as the series’ timeline ran closer to the present day, there was more research material, video footage, and literature to take on board.

“You get all the facts,” she says, “but you can’t act facts. At first you think, I can’t start from the outside; surely I’ve got to start from the inside and work my way out? But of course, we’re talking about a real person. And yet there are fictional scenes. So that’s the challenge and it’s a great challenge and one that I hope I have managed to conquer a tiny bit. It’s been really hard, I’m not going to tell you a lie. It should be hard. It’s such an extraordinary piece of work to be involved with.”

Staunton’s “reign” has taken in years in which the royal family came under more scrutiny than ever before, reflecting a rapacious media and the dawn of the modern cult of celebrity. “For the first time in the 90s people started to look and investigate what was going on in the royal household a lot more than they would have done, say, in Claire Foy’s seasons,” says Staunton. “People were much more intrusive into their lives in the 90s so that’s another issue as well.”

With the advent of Diana as the People’s Princess, it means that for the first time, the queen is no longer the lodestar of the family. She, after all, was very much the People’s Queen when she ascended to the throne in the postwar years. Yet Staunton says her queen sees Diana as less a threat than a counterpart.

“The papers were ruthless with her,” she says, “But I think the queen found it almost like, ‘Why are they using this language with this young woman who’s just trying to do her job?’ and she was more sympathetic to that than we realize: ‘Just let Diana do her job and stop hounding her.’ A lot of people thought she was jealous of Diana. Not at all, because Diana did a great job.”

The importance of getting on with doing the job once again emerges as the core of the queen’s motivation, in the eyes of all three of the actors who have played her. She was a human being, yes, but duty always came first.