The Crown takes on Princess Diana: Exclusive pictures and interviews

Charles has found a wife, Andy's got a racy new girlfriend and Thatcher's coming for tea... Megan Agnew gets an exclusive tour behind the scenes of the most wild and lavish series yet.

Lasers. That's what helped Emma Corrin understand Princess Diana in the latest series of The Crown. When the cameras were rolling, she imagined that lasers were pointing at her, as if she were in a spy film or a bank heist drama. It was her way of imagining hundreds of people staring right at her. Lasers helped her with the iconic Diana head tilt. She pretended she was shying away from them.

Corrin could also draw on her own trajectory as a 24-year-old actress. Before landing her part in The Crown, she was an unknown. Suddenly "there's a huge amount of pressure", she says.

When I visit the set at Winchester Cathedral, which is pretending to be St Paul's, the paparazzi arrive to catch Corrin pretending to be Diana. She's dressed in a replica of the outfit they papped at the actual royal wedding rehearsal almost 40 years ago. Every time she moves between buildings and trailers, Corrin has to be shielded with umbrellas. Life imitates art imitates life.

Almost every person Corrin has spoken to since getting the role has their own "Diana moment" — they might once have waved at her car in the street, been a pupil at a school she visited or knew someone who sat next to her at a dinner. Diana was one of the first celebrities to whom people laid claim. "Everyone has this ownership," says Corrin. She was, and still is, the People's Princess. But Corrin is trying not to think too much about it. Public expectation has been "overwhelming since the beginning", she says. She wants to do Diana "proud". "I know that's strange and cheesy, but I feel like I know her."

The first television series of The Crown, which aired in 2016, was at the time the most expensive in history. Each series since has been estimated to have cost upwards of £50 million. The first two covered the first decade of Elizabeth II's rule to wide acclaim, but series three — in which Her Majesty Claire Foy was succeeded by Olivia Colman — had mixed reviews. "The jewel in Netflix's tiara has lost its shine," said one. It was "okay", said another.

Now, with series four's reported £100 million budget eclipsing the Queen's own sovereign grant last year of £82.2 million, The Crown is barrelling straight into the Eighties era of celebrity glamour and modern party politics grit. Peter Morgan, the show's creator, is taking on two of the most controversial public figures of the past 50 years: Princess Diana and Margaret Thatcher. "The word 'iconic' is overused, but in the case of these two women quite justified," Morgan says. Both have passionate fans and detractors. "Writing them was a bit of a high-wire act, but it was exhilarating."

We meet Diana as a teenager, scampering around her huge family home in Northamptonshire. She is young and apologetic. The Prince of Wales, at that time dating her eldest sister, is rather distracted. A number of years later, Diana is leaving her relatively modest flat in Earls Court and her job as a nursery school assistant to move into Clarence House — but finds herself in solitude. Bored and lonely, 19-year-old Diana rollerskates down corridors to Duran Duran and sits all by herself in her chamber. One night, after finding out about Prince Charles's affair with Camilla Parker Bowles, she gorges on puddings and makes herself vomit them back up.

Behind the scenes: the latest series of The Crown. Photo / Netflix

It is a dark moment that Corrin wanted to get right. She listened to real-life accounts of people who had suffered from bulimia and talked with experts from the eating disorder charity Beat. Diana herself said that it was the most "discreet" way of harming herself: "Everyone in the family knew about the bulimia," she said in recordings from the 1990s later made into a Channel 4 documentary.

"Drawing on my experience," says Corrin, "not that I've experienced that kind of self-harm, but mental health in general, it can lead you down a very dark path when you're struggling to cope, when things feel out of control. Diana very much doesn't have the love and comfort and attention she needs from the man she loves or the family, who aren't really acting as a family to her. There is a build-up of emotion she can't deal with and making herself sick is a way of taking back control."

When Josh O'Connor, who plays the Prince of Wales, first read the script for this series he thought: "Oh God, how can Charles be like that to Diana? But he feels wronged. He feels like she has an addiction to the spotlight," he says. "I have to feel sympathy for him in that world. This is a family who have an intense inability to be emotional and he has inherited that awkwardness. In this series there's an awful lot of Charles trying to explain himself and not being allowed to. He's trying to say that if he can be with Camilla, then at least two of the three people can be happy. As it is, there's three miserable people."

The Crown works differently to other shows in that the "writers' room" is not made up of writers but researchers, who constantly feed back to Morgan, the king of The Crown. It means that for each word eventually spoken on film, there are pages and pages of briefing notes. Annie Sulzberger, head of research, started this series by hiring a young team. "I wanted people who did not grow up believing one or the other [Diana and Thatcher]," she says. "You have to be curious enough and ignorant enough, I suppose, to write the kind of work we need."

This series will span the Thatcher years — 1979 to 1990 — and will include the assassination of Charles's great-uncle, Lord Mountbatten, by the IRA, Charles and Diana's wedding, and the Falklands War. Once the team has laid out a timeline, Morgan picks out the events he wants to feature. The research team starts to hone in on each, getting increasingly "micro" in their investigations. In the making of this series, one of the team spent two weeks researching the label on a bottle of wine from which a character briefly swigs.

Dress rehearsal: Josh O'Connor and Emma Corrin act out Charles and Diana's wedding run-through. Photo / Netflix

As the show has progressed, the fact-checking work has multiplied, thanks to the tabloid journalism of the 1980s. "It's not just about words being printed," Sulzberger says, "but who wrote it. Diana will become very close with a journalist called Richard Kay and feed him information, and Charles's team will do the same. So you need to start unpicking the biographies of all the writers in order to know that what you're doing has some objectivity."

Did the team speak to any of Diana's family or friends? "No." Do the producers give any material to the Palace to see beforehand? "No. We have no connection to them that would result in editorial shifts. These are real people, these are real stories and we are filling in the moments that aren't recorded — private conversations, moments of reflection, philosophical moments."

When I ask Morgan if it's true that he meets high-ranking courtiers four times a year, he is keen to clear up that he doesn't. "I have never had any discussions with anyone actively working at the Palace," he says. "The two worlds, the royal household and The Crown, exist in a world of mutual deniability, which I'm sure is every bit as important to them as it is to us."

Corrin, though, did speak to Patrick Jephson, Diana's private secretary, who appears as a fictionalised character in this series. "I got a sense of her joy from him," Corrin says. "He said she was so naturally happy. When she joined the royal family, she had come from living with flatmates in Earls Court and she was a very normal girl. Patrick said she was still full of that girlish silliness, very down to earth."

The couple themselves at the real thing in 1981. Photo / Getty Images

The executive producer Suzanne Mackie says that "particularly now" The Crown team feels a sense of responsibility "to living people, people's children, people's parents. Obviously what we don't do is engage on a fact level with the royal family. We have a tacit understanding that they need distance from us and we need distance from them."

It is a cold day in January and I am watching Charles and Diana's wedding rehearsal in Winchester. About 75 per cent of the show is filmed on location around the world, over the course of seven months. The rest is filmed at the show's base, Elstree Studios, just north of London.

Today in Winchester Cathedral there is a crew of 78 and a cast of almost 200. The sight is as epic as the show's budget would suggest. Between takes, Corrin sits on the stone steps by the altar, scrolling on her iPhone with one hand and biting her fingernails on the other. Even before the clapperboard snaps shut, the resemblance between her and the princess is uncanny.

Sidonie Roberts, head buyer and assistant costume designer, has a timeline of photos of Diana covering the wall of her studio at Elstree. Roberts is devoted to the cause. She travels to Paris to buy buttons from the same shop the Queen's dressmaker uses (it sells more than 30,000 types of button) and to Soho to rummage in basements for fabric. Last year she was in a Bangladeshi fabric shop in Brick Lane, east London, when she saw a roll of material right on the very top shelf. "It was still in its plastic, but I just knew — that's Diana's colour," Roberts says. She got a ladder, climbed to the top, pulled down the fabric and bought it for £3.50 a metre. When Roberts got back to the studio at Elstree, she unrolled it and saw a stamp at the bottom: "The Lady Diana Collection, made in Japan." Roberts did some research. It was real silk, from a collection made in the princess's honour.

In the corner of the studio an assistant is gluing tiny pearls to Diana's flat wedding shoes. She has been decorating them, exactly like the originals, for a day and a half. "We've had a long conversation about the size of those pearls," says Roberts. David Emanuel, who designed Diana's original wedding dress, had in-depth conversations with The Crown's chief costume designer about the original sketches and designs – and from there, the team made the dress. With its 25ft train, it took ten people to get Corrin into the dress. In the show it is seen in full, and only from behind, for no more than 15 seconds.

Paying their respects: Olivia Colman as the Queen and the rest of the royal family at the funeral of Lord Mountbatten. Photo / Netflix

Corrin is masterful at inhabiting Diana's coyness — hunching her shoulders towards her ears as she walks, the smirk, her intonation. Diana's voice was the "polar opposite" of the royals', says William Conacher, The Crown's dialect coach. "She moved her jaw twice as much, so her voice was more forward, open, easier to access, and I don't think it's especially revelatory to suggest accessibility was her shtick," he says. "She used a minor key that made her seem vulnerable. Despite the Queen's and Prince Charles's accents being 'stiffer' to listen to, I think it comes entirely naturally, whereas I find Diana's voice more studied. I think she spoke to have an effect."

What sort of research did Colman do for series four's Queen? "Yeah, I don't do research," she says when we speak on the phone in the summer. "The research team on The Crown is a bit like the British Library. It's extraordinary, and when they kick in, your computer can't really cope with the amount of stuff they send you." Was there something in particular that the team sent her that made things click? "No." There is a longish silence. It seems Colman's royal duty is waning. "They've got every image and film of the Queen ever made. I've also got three kids, so I can't spend all my time going through all of it."

As she wraps up a second series of The Crown — Imelda Staunton will take over for five and six — Colman knows that she would "really not like" to have the Queen's job. "There are very few people who are forced into a job and have no choice about it," she says. "She's done it with dignity, for decades, bless her. It's amazing."

The funeral of Lord Mountbatten took place in 1979. Photo / Getty Images

If there were rumours of Elizabeth II being unhappy about the last series of The Crown, I can't imagine she'll be too chuffed about this one. Series four's Queen is colder and more distant, and the effects of her duty on her children more obvious: Charles is heavy with melancholy, Anne feels unheard, Edward is portrayed as a spoilt bully and Andrew is dangerously arrogant.

Speaking of Andrew, there is a subtle nod towards recent events. At one point the prince discusses a young American actress he is dating. The actress had recently played a 17-year-old who must entertain several "old predators who seduce the vulnerable, helpless young Emily". The real prince dated the actress Koo Stark in 1981, who had starred in The Awakening of Emily, which had a near-identical plot.

In series four, the pivotal relationship between the Queen and Margaret Thatcher begins well. They are respectful of one another as no-nonsense working mothers, but tensions arise — not least, over tea etiquette at Balmoral.

In preparation for her role as the Iron Lady, Gillian Anderson met Charles Moore, Thatcher's biographer, as well as secretaries who worked with her. "The only way for me to go about sitting inside of her was to find the reason behind her actions — growing up, what she learnt from her father, how much she truly believed that she was the answer and as long as we all took the sour medicine now we'd be able to turn around this country, completely shutting her eyes to the people that she was turning out on the street."

Anderson eventually "settled into" the body of Thatcher. "She walked very fast, always up ahead," Anderson says. "She would power forward in front of presidents. With [Ronald] Reagan she would supposedly be alongside him, but was walking ahead. Always walking ahead of [husband] Denis, telling him to catch up."

Thatcher's barnet also features. In one scene she spends an asphyxiating four seconds hairspraying it in preparation for a showdown with the Queen. The hairdo took endless camera tests before Morgan was happy with it. "It essentially meant destroying it so it had an overprocessed 'frothy' quality," says the hair and make-up designer Cate Hall. "To treat a wig so badly was against all of our instincts — they're so expensive — but I'm grateful now that we went through the process with Peter, with him saying no, more, it's not right, try again."

Clash of the titans: Margaret Thatcher, played by Gillian Anderson, is filmed meeting the Queen, played by Olivia Colman, in a memorable scene from series four. Photo / Netflix

Series five will have a whole new cast. Colman says she is "not the sort of person who keeps the shoes of a character they played 20 years ago". But Helena Bonham Carter is going to miss Princess Margaret. "She does pop out [in everyday life]," she says. "The other day I was at some public event and there was the normal scramble of people and I just told them, 'No, shut up.' The finger came out, which is very her, and I said, 'Shut up and wait. Don't get hysterical.' So I've got the bossy side of her."

Originally Morgan said there would be two more series after this one. Then he changed his mind, describing series five as "the perfect time and place to stop". Now there are two more again ("To do justice to the richness and complexity of the story," he reneged). The show is creeping closer to the modern day. It is now said to be ending in the 2000s, spanning, perhaps, Charles and Diana's divorce, the deaths of Diana, Margaret and the Queen Mother, the marriage of Charles and Camilla, and the teenage and twentysomething princes. "I want to end it close enough to present day to feel that we have completed a long journey and distant enough to feel historical," says Morgan. "I have a specific incident in mind, but until I've actually written it and seen if it works, I can't commit to discussing it."

On set with Mackie, I mention Harry and Meghan. "Too often," the couple posted on their Instagram page that month, "we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring." Is it possible, I ask Mackie, for the royal family to humanise themselves while still justifying their existence as something mightier, more important, regal? "That's where you go wrong, as a public figure, letting light in on the magic, especially as a monarch," she replies. "You have to be an ideal. After years and years of that subjugation of self in order to put duty first, you, the essence of you, is buried somewhere. The Queen is a tiny little person inside many, many Russian dolls."

Series four of The Crown is available on Netflix from November 15.

Written by: Megan Agnew
© The Times of London