“SHE was just so different to anything I’d ever read before,” Florence Pugh is saying. “She was just so exciting, and so manipulative, and delicious. I’ve never had a character allow us to love her whilst she does awful things”.

Awful things is an understatement when it comes to Katherine, the anti-heroine whom she plays in a new film, Lady Macbeth. The film has just gone on UK general release, trailing the sort of advance reviews that most film-makers would kill for. Pugh herself has drawn praise from critics who know what they’re talking about.

The film, the debut feature by theatre director William Oldroyd, is based on a 19th century novella, Lady Macbeth of Mtsensk District, by Nikolai Leskov (and despite the title, it’s not about the Shakespeare character).

On screen, the action has been transported to rural Northumberland in 1865. Katherine, 17, having been sold by her father, together with a small piece of land, finds herself in a large, austere country house and, worse, in an arranged marriage to a curt and distant older man, who resolutely declines to make any physical advances to her, even on their wedding night. And her new father-in-law is as harsh as he is unsympathetic. Her future looks bleak, but Katherine is not without resources.

In time, she falls headlong for a groomsman, Sebastian (Cosmo Jarvis), with whom she begins a torrid affair. Gradually, however, she, and the film, take a violent turn as it becomes evident that she will stop at nothing to get what she wants. It says much for the script (by Alice Birch) and for Pugh’s remarkably self-assured performance that, even at the end of the film, having witnessed a fair degree of mayhem, we still can’t bring ourselves to dislike Katherine.

Pugh herself has won acclaim for the role. Declaring that she had announced herself as a major talent, the US entertainment bible Variety praised her for folding Katherine’s contradictions “into one composed, consistent characterisation” and that she “impresses with precocious poise, sensuality and venom”. Given that this is really her first major role, and that she is still only 21, it’s hard to disagree with Variety’s judgement.

Pugh was born and raised in Oxfordshire. At school, in Oxford, she was, by her own admission, no good at chemistry or maths, being much more inclined in the direction of drama and music. She took part in a city arts centre’s productions of such plays as Romeo & Juliet and Blood Wedding, and she was already thinking of a career as an actor when fate intervened in the shape of The Falling, a 2015 film directed by Carol Morley and set in an all-girls' school.

“I nearly didn’t do it,” Pugh says of that film. “I wasn’t going to do it. My brother’s in the industry, and I had been watching him for a couple of years before I had done that audition. I knew how mean the industry was, I knew how cut-throat it was. I knew that you just don’t get auditions like that.

“So obviously, when I saw that ad – to hand in a tape – I didn’t do it, because there was no point, because I wasn’t going to get the part. And then my mum said, well, this is what you want to do at some point. You’re not going to get the role, but we can always just give it a go because you need to start knowing how to do tapes.

“So, on the day of the deadline, I rushed over and we quickly filmed myself talking about my hobbies, who I was, and what it was that I did, and I got a callback the next day, saying the director wanted to meet me at some point. So it was all pretty much fluke, and being in the right place at the right time.”

She subsequently did an audition in person for Morley. After she left the room, Morley thought, oh wow. The casting personnel fell quiet as they weighed up what they had just seen. “Do you not think she’s amazing?” Morley asked. Someone else said it was like a young Kate Winslet walking into the room.

Pugh has a small but central role in The Falling, and if she appeared daunted by working with Maisie (Game of Thrones) Williams, with Maxine Peake and Greta Scacchi, she did not show it. That said, her first day in front of the camera was, she acknowledges, “absolutely terrifying, and I remember feeling sick on the way to work, because I’d done a whole summer’s worth of auditions, and I’d worked so hard to get this role," she says.

“I remember [on that first day], getting in the car and thinking, oh God what if I’m crap? What if all of this is a lie, and I’ve managed to wean myself into this role and I completely muck it up? The first line I had on camera is where me and Maisie are under the tree and I say one line. It’s a very simple line. There was a big crew there … and the camera’s on, and they say ‘action’, and I’m looking up at the tree, and I just completely forget my line. Gone. I remember thinking, you really can't muck this up. Wake up!”

She needn’t have worried. After The Falling, she filmed a pilot, Studio City, for Fox. Most recently, she was seen in ITV’s Marcella, alongside Anna Friel and Laura Carmichael. And last October she was one of 20 talented newcomers to win a BAFTA Breakthrough Brit award.

Casting director Shaheen Baig had cast The Falling and she recommended Pugh to Oldroyd when the search was on for someone to play Katherine. It had to be someone capable of playing an innocent young woman who becomes considerably more cold-hearted. Oldroyd himself had seen The Falling and thought Pugh had been “open and honest”. And straightaway, they knew they’d found their Katherine. Florence, Oldroyd says, “gives an incredibly strong and confident performance”.

And now, after numerous screenings at film festivals, comes the widespread release of Lady Macbeth. “It’s very rare,” Pugh says, “that a script like this lands in my inbox – especially, you know, being given the opportunity to … at the time, I was a still-unknown 19-year-old actress, and that just really doesn’t happen.” It was “such an exciting prospect to try and get under the skin of” someone as manipulative and delicious as Katherine, she adds.

“The most fascinating thing about her is that we still love her until the end. Even if you don’t love her at the end, she still managed to allow you to support her. For a character to try and play, that’s fascinating."

The film also makes you think of the repressive way in which many women were treated back then. “One reason why I believe this character is so brilliant is that she is a modern woman in 1865. This wasn’t the norm, back then: it was totally expected that the woman was bought by her husband, and she was his property, and she would do exactly as he said.

“And of course Katherine – she’s 17 and she has been forced into this marriage – and she says no, which is rare. All of us that know period dramas were not expecting that. We don’t expect to see a modern force in an 1865-period film.”

Lady Macbeth sees Pugh wearing some authentic, striking gowns, but the tightly-laced corsets that Katherine is tied into by her maid Anna (Naomi Ackie) were a key way to understanding her.

“We went up about two weeks before we started shooting, and we had rehearsal time. We would be doing all of these physical scenes, me and Cosmo, and of course the moment I got in a corset, it all changed, because I couldn’t do that. I couldn’t move.

“That was so eye-opening in terms of Katherine and the character, because it meant that she was just as serious about these things as I was, and essentially her happiest times were when she was in a nightie or she was naked or she was in a dressing-gown, because that’s when I was at my happiest.

“There are so many ties that I could pull between me and Katherine because of that corset. It also made me realise how imprisoned these women were in 1865. They were trapped in their own clothes.” The corset, she adds, squashes your internal organs. "It’s designed to do exactly what it does, and that’s to keep a woman quiet.”

Pugh has gone on to shoot three upcoming films. The Commuter is an action thriller with Liam Neeson and Vera Farmiga; in Hush, a Sigma Films and Thruline Entertainment production, filmed in Glasgow and Ayrshire, she and Ben Lloyd-Hughes play two siblings who run a profitable ghostbusting racket. “Florence is a very unique talent, a special British talent on the rise,” says Brian Coffey, co-producer of Hush, “She has a deeply intuitive ability to create characters that draw an audience in. We were thrilled to be able to cast her

in Hush.”

The third film is Stephen Merchant’s Fighting With My Family, in which Pugh plays a real-life WWE wrestler called Paige. The cast also includes the substantial presence of The Rock, Dwayne Johnson.

One scene in the film recreates Paige’s wrestling championship victory in a Monday Night RAW event in Los Angeles. Before Pugh stepped out into the ring, she had a brief rehearsal with The Rock. Speaking on Women’s Hour this week she said: “He’s teaching me how to throw a punch and I was stood there, and I remember looking at him, and just this space behind, all the empty seats, and thinking, oh my God, Dwayne 'The Rock’ Johnson just taught me how to punch!”

All in all, it was a marvellous experience, as evidence by Pugh’s Instagram post: “One of the best, most terrifying, most knackering and unbelievably exhilarating shoots I've ever done. #fightingwithmyfamily has wrapped and my god has it been a good run.”

She tells the Sunday Herald that she’s excited about both Hush and The Commuter. "Fighting With My Family was an emotionally and physically draining film, because it was so much fun but also because we were playing those wrestlers," she says. "Jack Lowden played my brother and it was really wonderful. We learned how to wrestle together and we had a lot of fun.”

There’s nothing else in the pipeline at the moment, though. For the time being she is focusing her energies on helping to promote Lady Macbeth – she’s excited to see what people think of it. Afterwards? “I’m going to have a little bit of time off, because I’m knackered. And then I can see what happens to Lady Macbeth, see where it goes.”

I ask her about her favourite films. “I love Leon,” she says, “I love Eternal Sunshine [Of The Spotless Mind]. I tell you what: I bloody love all of Natalie Portman’s stuff." She asks if I’ve seen the film, Chicken. “Oh, you should watch that,” she enthuses. “It’s by a new director called Joe Stephenson and there’s a great actor in it called Scott Chambers, who I worked with on Hush. It’s just absolutely beautiful.”

It’s only once the interview is over that I remember that Florence Pugh has yet another string to her bow. On her Twitter bio she describes herself not just as an actor but also as a singer-songwriter - she plays acoustic guitar, and sings, in a tantalisingly brief scene in The Falling. If for some reason she doesn’t make it as an actor she could, you imagine, always turn to writing and singing songs. But her performance as the manipulative, quietly riveting Katherine in Lady Macbeth suggests that her acting career is already on the firmest of footings.

IS IT TOFF AT THE TOP?

THE issue of so-called "posh" actors dominating the profession at the expense of those from less privileged backgrounds crops up frequently. Two weeks ago, Eton-educated Damian Lewis rejected the idea that they dominated acting, but called for greater diversity in the arts.

“I can certainly say that I didn’t have a difficult childhood. I had a really wonderful upbringing,” says Florence Pugh. “Obviously, [the alleged dominance] must be an issue, because it’s coming up, and people are obviously very opinionated about it.

“I haven’t been doing this for very long but of course I’ve been called this and that. And because of the speed with which my career has gone up, people have questioned whether it’s because of where I’ve come from, or where I went to school, or whatever. And I think my main comment towards it is: obviously, it must be frustrating to see people of privilege to go so high, but at the end of the day it’s the same game to get into this industry.

“It is just as hard, and everyone’s stories, left or right, have their own challenges in it. It is not easy to win over the public, to win over the critics. And yes, essentially, you could get in the news a lot if you’re privileged, if you have money, but it’s what you do with that afterwards. If people continue to watch your work, then surely that’s down to your talent.

“If they don’t, then you can call them out on it. But because this industry is so difficult, to stay in and to get there, I don’t think anybody should be accused of how they got there – unless they haven’t proved their point.”