When Alexandra Shulman greeted us in the spacious office in central London (in the headquarters called Vogue house, of course), I couldn't help but notice the display of Vogue's international editions on the wall.

"Shame, I can't read many of them. I can't really judge them apart from the imagery," says Shulman. "When you look at those magazines, every cover is so reflective of the culture it comes out of. We have India, Japan and so on. I don't think I could've put butterflies on the British Vogue cover, but they put them on the cover in Russia because they like their theatricality."

When asked if she could be an editor in any other country, she admits probably not. "I'm successful here because I understand the British culture," said the editor-in-chief.

Shulman has a firm stance and an assertive voice. Her workspace is decorated with a personal touch, but without feeling cluttered. There are archives of Vogue issues from 1992 (the year she started) onwards. It's a chronicle of staggering 24 years of British fashion neatly kept in sets of green folders.

This year, British Vogue celebrates its 100-year Jubilee. So what does it take to be the woman in charge of one of the most influential fashion magazines in the world? We find out.

I think Vogue  is lucky because it's not just another fashion magazine. People want to keep it. Very few people buy it, read it on a train and then chuck it out. What is the secret to your longevity at Vogue?
Understanding of what Vogue is and the ability to see what's happening around you, and understanding of how to accommodate that. Just because somebody's been on everybody's cover doesn't mean that I want to have them on mine. What's important is to feel that you're  looking around and taking note of what people are interested in, and how people are engaging with what you do. There is the print magazine, which is still my passion, but I can't deny that there are so many other strands now that take up my time.

How heavily involved are you in the digital aspects of the magazine? Has digital affected print?
I'm an editor-in-chief so I'm overseeing the digital. We have an editor, Lucy Hutchings who edits the website on a day-to-day basis. We have Vogue on an app, we have mobile Vogue, and we are making more and more videos. We have a lot of people engaging with Vogue online because it's free, but we know that a lot of people still want to buy the object. They want to keep it and they like the experience of reading the magazine. If you look at iPad sales of the magazine, they are relatively small. I think Vogue is lucky because it's not just another fashion magazine. People want to keep it. Very few people buy it, read it on a train and then chuck it out.

You sound a lot like a businesswoman. Would you describe yourself as one?
I am definitely a journalist and a bit of a businesswoman. However, I don't really see myself as a fashion critic per se.

Who dictates fashion these days? Fashion critics or celebrities?
I think it's a broader constituency of voices that are heard than it would have been 20 years ago. It's not that celebrities dictate fashion — it's just a public reaction to that celebrity and what he or she was wearing. I think fashion is still mainly driven by designers, magazines, photographers, and the imagery created around it.

What do you think of street style as a phenomenon?
Street style has always been interesting, particularly in this country. It's actually very influential — but that's proper street style. I'm really uninterested in the street style circus around places like the shows or the idea of people just dressing up in order to be photographed.

What do you think of the red carpets?
To be honest, I think red carpet is something people walk along to go to a ceremony. I don't see why it has to be in any way a fashion show. Personally I think that quite often the girls look better when they're dressed safely than when they wear some kind of extraordinary outfit, which might be very strong in terms of innovation but doesn't necessarily suit her.
Would you say fashion as a whole has also become safer as opposed to being bold and experimental? 
I don't think it became so much safer. If you look at Comme des Garçons, Givenchy or McQueen, there's always been a level of fashion that's very creative and conceptual that carries on. But there are more labels and people consuming fashion underneath that fashion pyramid.

Are there any British brands today, which deserve more recognition in your opinion?
The British brands are growing. I think we've got fantastic designers now and they're getting a lot of recognition given that they're relatively small businesses. Mary Katrantzou is a good example of somebody who's got a very strong vision and her shows have always been pretty conceptual.

Is fashion business or art?
Fashion can be an art and can be a business. You have to decide what you want to do with it really.

What is your personal stand on that?
I'm probably slightly more inclined towards business. For me, I like the idea that people actually buy fashion.

I always hire people based on whether I like them or not, much more than based on their qualifications.

What do you still find challenging for you at Vogue?
Everything. I'm here all the time, read or write every cover line, every caption on every page, look at every picture and approve every shoot. I never think: "Oh, that issue went really well!"

There must've been issues, which you were really proud of...
I did love the Millennial issue in December 1999. It was brilliant and sold very well. This year, we're going to have a Centenary issue because we turn 100 years old. This is my new challenge — a year of celebrations.

Hundred years is a lot for a magazine...
It is and it started in 1916 so the majority of the contributors are no longer alive. You don't want to celebrate by only looking back. You also want to look forward. Besides there wasn't a lot of photography for the first 30 years of it, there were a lot of illustration.
In The Devil Wears Prada, it was said that a job at Vogue is one "a million girls would kill for". How does someone get a job at British Vogue without committing murders?
We have quite a lot of people who started working here who came through the work experience programme. Of course, you need to apply for the job and do an interview, but I always hire people based on whether I like them or not, much more than based on their qualifications.

How can one make you like them?
Write a really good letter with a reason why perhaps I should meet you (smiles).

Have you ever thought of leaving Vogue, and why?
Yes. I don't know, perhaps got out of bed with a bad temper that morning? I mean, obviously you think what else you might do in your life and I think about it a lot.

What conclusions do you come to?
I know that when I leave Vogue, I would probably do something different.

In the new world of declining print press and rising social influencers and YouTubers, what kind of journalist do you think you would have become if you started your career today?
It's such a great thing that happened to me. Journalist is a wonderful job, but so much harder to earn a living off that these days.

Do you think YouTubers represent a new breed of journalists?
That's a different career, is it? It's a YouTube video maker. I'm not sure what the definition of journalism is — I have to look it up. But I think of journalism as of something involving writing. It's a big moment of change right now. In the end, there will be careers involving lifestyle, but at the moment it's slightly unclear how and what form it's going to take.

How does Vogue attract new generations of readers?
We have the Vogue Festival and people come and spend a day in the environment where we have talks, make-up demonstrations, and styling. Last year, we had Galliano, Gaultier, Christian Louboutin and Alexa Chung doing talks. You could also do a speed styling challenge and get fashion advice. That attracts a pretty young audience, and in general, I think young people love Vogue. There doesn't seem to be a problem with engaging young people. I guess due to the way we communicate now, we reach a much wider audience.