And win it shall. The most expensive television series in history, at least on a dollars-per-hour basis, The Crown is a compelling fusion of history, soap opera and constitutional tutorage, charting the rise of Queen Elizabeth II from naive young princess to the most influential woman in modern history. Equipped with a pedigree cast, unprecedented scale and a price tag of £100 million it is a certain hit.

"I don't think you could do a show about the royal family without having the scale," Claire Foy, the 32-year-old Wolf Hall star who is playing Elizabeth, says. "It wasn't like we were walking around dripping in gold, but I would walk on set and be like, 'oh my goodness'. You never had to imagine anything because it was all there."

The series, which covers "the two most famous addresses in the world, Buckingham Palace and 10 Downing Street", explores Elizabeth's marriage to Prince Philip (Matt Smith), her relationship with her sister Princess Margaret (Vanessa Kirby) and, most significantly, her relationship with British prime minister Winston Churchill (John Lithgow).

It is, says director Stephen Daldry, "not just the story of a family, [but] the story of post-war Britain".

To set the scene: young Princess Elizabeth, engaged to be married to a dashing prince of Greece and Denmark, is the daughter of a much-beloved King George VI whose reign has functioned as an antidote to that of his brother, the earlier, imprudent King Edward VIII, who abdicated to marry the American divorcee Wallis Simpson.

The road to coronation for Elizabeth would have been a long one but for the unexpected death of her father, aged just 56. Returning to Britain from Africa, the now-Queen Elizabeth II must contend with a raft of political and personal crises and a succession of prime ministers, beginning with the formidable Churchill. She was just 26 years old.

Lost, somehow, in the media narrative is the humanity of the woman, says Foy. Her succession to the throne is observed with little understanding that on top of everything else, she was still a young woman grieving over the death of her father, a man to whom history records her deep devotion.

"That was our job in a way, to bring humanity back to this amazing life story," Foy adds. "It's a funny thing about power ... so many people say to me how powerful she is and I think she would think she's the opposite. I think that she would think that she has no power."

Central to the story are a series of complex relationships, but none so complex nor intangible than Elizabeth's relationship to "the Crown", which almost begs for someone to say "there were three of us in this marriage", a line which would not be used for decades, and about another, more turbulent royal union.

At the heart of that, says Smith, are the two men in Elizabeth's life – Churchill, who represents her duty to the nation, and Philip who, at least in the infancy of their marriage, rebels against the idea of the Crown.

"For their whole life they have this huge cross to bear in many ways, particularly for Elizabeth there is this great pressure to fulfil her duty and that's why her relationship with Winston Churchill is so fascinating because Churchill makes it his sole motive to ensure that she upholds the credibility and the notion of the Crown," Smith explains.

Philip, in stark contrast, was something of an unacknowledged moderniser. "He rebels against the old form, the old guard," Smith says. "And he's kind of modernised the idea. Philip was the first one to hold a press conference, he was the first person to get the press involved, which is odd now considering his relationship with the press."

The series is written by playwright and screenwriter Peter Morgan, whose credits include the films The Queen and Frost/Nixon and the play The Audience, about the Queen's weekly meetings with her prime minsters. Two of those productions – The Queen and The Audience – starred Helen Mirren as Queen Elizabeth II.

For both Foy and Smith, taking on the roles was less about imitation and more about striking a resonant, and reminiscent, chord. That is slightly at odds perhaps with Mirren's approach to her role, which was an almost step-perfect imitation of Elizabeth's gait and mannerisms. Or even Michael Sheen's brilliantly studied mimicry of Tony Blair in The Queen.

"This isn't Spitting Image; we're not doing caricatures of these people," says Smith. "We're trying to capture a note of them, a chord of them, an energy of them, a tone of them, a colour of them. Then express that and be inventive with it but also be as truthful to them as people and pay them as much respect as we can."

Foy says the simplest way for her to approach the work was to simply treat it as fiction, though many of the events in it are documented history. "We have no contact with [the royal family] so it is fictional in my head," she says. "It has to be. It can't be based in reality in that sense because it is fictional. Peter has had no kind of influence from them either."

The faux royal residence which features in The Crown is located in a far corner of the Elstree Studios in Borehamwood, north of London. Though the studio surrounds have a grim, worn quality, particularly on the freezing, foggy morning when Spectrum visits, this is where they made Star Wars in 1977, and the Indiana Jones films. If you are hoping for a glimpse of Hollywood in the English countryside you can't do better.

Trudging across the gravel towards the back of the studio, the real scale of it all comes into view. Re-created here is a giant mock-stone facade, the so-called "east front" of Buckingham Palace, the final piece of an architectural jigsaw which completed John Nash and Edward Blore's piecemeal palace in the late 19th century. It includes the balcony from which a century of iconic moments have been punctuated with a wave from the monarch.

On a neighbouring soundstage are re-creations of the palace's interior, including the reception hall, the state rooms and the Queen's bedroom, and in another the interior rooms of 10 Downing Street. The most immediately striking thing about it is the scale of the production and its attention to detail. Nearby props and wardrobe departments are packed with gowns, suits and royal robes, including a stunning recreation of the Queen's wedding dress, originally by Sir Norman Hartnell. Fine detail, such as books, brands of tinned food and even toys, are carefully checked for accuracy.

Beyond that are rooms where boxes with scribbled labels stacked on shelves make a rather incongruous Aladdin's cave of jewels, diamond-studded brooches and other regal finishing touches. The more elaborate pieces, such as Queen Alexandra's Kokoshnik tiara, which featured frequently in the early years of the Queen's reign, and the Grand Duchess Vladimir tiara, the Queen's most famous headpiece, are, though copies, safely locked away.

"When you get down to it all film sets are exactly the same," says Foy. And yet in The Crown, she concedes, there is a difference of scale and tone. "No expense was spared with the locations or the difficulty of getting to location," she says. "A lot of the time corners are cut because they have to be but I have never felt like we were cutting corners. We never cut a scene, we never cut anything because it was too difficult. That's why it's different."

The filming locations, such as the neo-palladian English country house Wrotham Park, in Hertfordshire, which stood in for Buckingham Palace, and Ely Cathedral, in Cambridgeshire, which stood in for Westminster Abbey, are equally exquisite. (The former of those two was, in real royal life, used for a pre-wedding reception for Crown Prince Pavlos of Greece and his wife, Marie-Chantal Miller, in 1995.)

Ely Cathedral features in two key sequences: as Westminster Abbey it is both the location of the royal wedding between then-Princess Elizabeth and Prince Philip, and later, it is the scene of the Queen's coronation, when Elizabeth is anointed with sacred oil, takes the Coronation Oath and first wears the the Imperial State Crown.

"Placing the crown on her head pales in significance to what happens under the awning where the Archbishop of Canterbury anoints her and she is essentially, is at that point, in union with God," Foy recalls of the intense emotion during the filming of those sequences.

"I think that, for her, the pomp and the ceremony and the state occasion is very important to her, but personally, not being the Queen for a moment, and just being Elizabeth, [the anointment was] I think the most important moment for her. That felt like the most important moment to me."

On a personal level, for Foy, the royal wedding was far more nerve-racking. "The [pieces of the ] coronation were actually shot over about 40 days, but the royal wedding felt like an actual wedding," she says, laughing. "I was terrified. You suddenly sort of went, oh my god, there's my mum, there's my dad, there's the Queen of Denmark."

In many respects, The Crown is pure soap, a sort of art-imitates-life tangle given the real-life soap opera of the House of Windsor. It also represents the maturation of a genre which has historically been largely American-funded telemovies and miniseries, with turgid titles like Charles and Diana: Unhappily Ever After, Diana: Her True Story and The Women of Windsor.

Few of those projects are memorable, indeed many are laughably poor, though the last of those is notable because it featured the model, food consultant and former editor-at-large of Tatler magazine Nicola Formby as Princess Diana. (For the record, she was quite good. And unlike Naomi Watts, she managed to get the hair right.)

"Dealing with this subject matter with some degree of respect, you know, even objective scrutiny, is a rare thing," Morgan explains. "These are people who are used to slander, cartoons, satire. These are not people who are used to being taken seriously. And whilst that might be a terrifying prospect, I think it is also the only worthwhile way of looking at our recent history."

And while it uses a political backdrop to drive its narrative, it is still a great love story. "There's a very profound love," says Smith. "I think in many ways they are great soul mates. They've come such a long way together.

"Like any marriage it goes through very difficult periods, it goes through ups and downs, and we explore the difficulties that they experienced because of her responsibilities as Queen, and him feeling slightly emasculated and wanting to assert himself in his own way," he adds.

On a more political note, the curious question of the Palace's awareness of the project is a tricky one to navigate. They certainly are aware, says Morgan, though to what degree he is unsure, or not saying. Maybe he's being diplomatic. Maybe he knows the less he says the more intriguing the question remains.

The Crown also tells the story of a post-war Britain searching for its national identity, a mood which seems to correlate with the post-Brexit present, in which, political machinations aside, it feels as though Britain is trying, once again, to come to terms with what it is and what it wants to be.

"I think whatever time you're in, whether it's after the war, you're assessing your identity in some sort of way," says Smith. "Whether it's the war in Iraq, whether it's 'are we doing enough in Syria?'. I think we're always questioning the way we react to things and the way we respond to things."

The decade makes no difference, Smith adds. "There's always something to respond to in the hope that you can be better in some way as a nation," he says. "I think the Queen has always put England at the forefront and sacrificed a lot for it."