Consolata Boyle, the Irish costume designer who worked her way up to become one of the most sought-after designers on the big and small screen, has worked with Brown through all three films in the series. She signed up for the first Enola Holmes film when Brown — also a star of Stranger Things — was still a teenager.

“It was wonderful, actually, right from the get-go,” says Boyle of working with the young star. “It's almost like being in a position of watching her grow up, through all the different ways that the script developed the character, and Millie obviously is absolutely central to all of that.

“I found working with her really rewarding. She's very involved in her costume, she has very strong opinions, and obviously they come from a working-through of the character.

“Particularly on Enola 3, Millie had a lot of involvement in her costume, and that was wonderful — I really enjoyed it. You are the controlling force, but there's so much freedom within that, and Millie's contributions were vitally important,” adds the Dublin-born 77-year-old. 

Known for her meticulous attention to detail and her character-driven designs, Dubliner Boyle has become one of the film industry’s most successful costume designers.

We’ve seen her work across multiple screen stories, including December Bride, Angela’s Ashes and Philomena. Her long-term collaboration with director Stephen Frears stretches back to The Snapper and led to all three of her Oscar nominations: for The Queen, Florence Foster Jenkins, and Victoria & Abdul.

There are practical as well as visual elements to the work she does, she says. “One thing that is very important with the Enola character is there are a lot of stunts and a lot of very athletic movement for Millie. 

"With all of her costume, even though you will notice when she's moving there are masses of skirts and petticoats flying, there's no minimising to make it look easier for her. All of that is built into the costume, so that you can move and achieve what's needed in the scene without any kind of distress, that she's able to literally throw herself around. 

"Millie does a lot of her own stunts. So those costumes and the stunt costumes have to work technically, and they need to work visually in telling the story.” 

Boyle, who has been on board with Netflix’s hugely successful Enola Holmes series from the outset, was drawn from early on by its storytelling power. The screenplay is the first place she turns to at the early stages, and informs a great deal of her research and the design choices she makes.

“If I was ever to try to describe how I work, I would say completely from the script, the costumes actually come towards the end of the process. What is the story? What are we trying to say? What is the overall message? I love the research process, and I spend quite a long time researching, and then a lot of the research is just put to one side and tiny bits of it are maintained,” she says.

It's the process of research she finds hugely creative, as well as talking to the other people involved in her team, the directors she’s worked with, the other heads of department across the production. “Everybody works together, everybody leans on the other, and the thing I enjoy so much is that it's a true collaboration.”

She says preparation differs greatly from project to project, as does the approach of filmmakers she works closely with to realise their vision for the look of costume in a film or TV show. 

“Some directors are very communicative and chatty, others are much more reticent and allow you to develop a lot on your own or with other members of the crew. They all have their unique way of being intensely involved, so that's vital, and then the research is running along beside that all the time. The palette, the fabric, the shapes, whether it's contemporary or it's period. 

"Every character will have a palette, will have all the nuances that go into expressing the inner life of every character. Then the nitty gritty starts, the measuring, the building of the costumes, and I work with an incredible team. I like as much making as possible, and finding, depending again on the film.” 

She has become a leading international name in costume design, yet Boyle says she didn’t imagine it as a career when she was young. The fact she ended up in costume design was like a series of things that happened to her, she says now. “The upbringing I had, and what has stayed with me, absolutely undimmed, is stories and telling stories. I suppose I was quite a dreamy child, and I had quite a strong interior life.” 

Following a degree in archeology and history, she took night classes at the National College of Art and Design, enjoying courses in life drawing, pottery and weaving. She knew from early on she didn't want to teach academically. 

“There was a wonderful opportunity at that time, which does not exist anymore, sadly, an apprenticeship scheme in the Abbey Theatre. I was very lucky I got in, and that's really where the whole thing started to maybe gel slightly.” 

During her apprenticeship, Boyle did “every single thing you could possibly think of”, including props and scene painting. “As I did more, I knew that I was leaning towards fabric and cloth, maybe because of the weaving that I'd done.”

Following a course in textile history and design in the UK, she started working on a freelance basis. People she knew were starting to make small films, and they asked her to work with them. “It was like a series of events that I just did, and it evolved into something, and suddenly I was a costume designer.” 

Most recently, she completed work on Cork-born filmmaker John Crowley’s next film, Walk the Blue Fields, starring Emily Blunt and Andrew Scott. Filmed primarily in Ireland, it’s an adaptation of Claire Keegan’s story collection co-produced by Element Pictures for Netflix.

Boyle is glad to be involved in the third film in the Enola Holmes series, and how it has captivated younger audiences in particular. “There's a lovely vulnerability about Enola, where she admits to being afraid, and I think that really spoke to young women and girls. I think that was very important, the celebration of cleverness and bravery, and yet vulnerability. On top of that, it's a lovely period, and there was a lovely free-wheeling atmosphere to everything.” 

• Enola Holmes 3 comes to Netflix from Wednesday, July 1