YOUdon't have to be an avid shopper or a student of retail patterns to know that the high street, as we knew it, no longer exists. When it's handbags at dawn for some of the country's most stylish women, trying to nab a Roland Mouret dress in Gap, or when Penneys produces one of last season's key items (a military style jacket), subsequently featured in Vogue, it's obvious that a seismic shift has occurred in the fashion world.

Through a series of canny marketing moves . . . faithful catwalk copies, designer collections, limited-edition cult items and bespoke services like personal shopping . . . the high street's previous reputation as purveyor of cheap tat has been banished. Quite simply, this is because high-street shopping is not always cheap and it's certainly not tatty. A French Connection frock might set you back 150 (not an insignificant amount by any means) and items from Viktor and Rolf 's range for H&M stay true to the design duo's sensibilities and might even be future collectibles. This Christmas, there is no shame in wearing a 30 New Look dress to the chicest of parties, although the true fashionista will accessorise with a pair of Marc Jacobs heels and a Prada bag.

Not all high-street stores are equal, however.

Certain shops are current favourites, although it's not possible to predict for how long this tenure will last. Kudos-wise, Top Shop still reigns and with all the excitement about next year's Kate Moss collection, its currency is as high as ever. Another flavour of the month, New Look, reportedly took in 60,000 in its first day when it opened in the Eyre Square Shopping Centre in Galway two weeks ago.

Monsoon, after a period in the doldrums, has upped its game with a rather cool new range called Fusion and Peter O'Brien's capsule collection for A/Wear brought a new, older, richer breed of customer to its stores. But then there are the stalwarts of the high street, the retailers who quietly and consistently sell vast amounts of stock but who . . . because they're never sizzling on a hot list . . . have never felt the chill of disfavour when fashion fixes its gaze elsewhere.

Karen Millen is one such example. It's fashionable, certainly, but not so achingly fingeron-the-pulse that it has to be discarded after a week's wear. More expensive than Top Shop or Oasis, it's not prohibitively so, and when you're in search of that classically cut, affordable and chic dress for a wedding or Christmas party, it's always a safe bet. Animal print is one of the season's biggest success stories but Karen Millen has regularly featured it in its last couple of collections, whether it was au courant or not. "We don't always follow trends, as much as we like to follow what's going on, " says Karen Millen, the company's founder. "We like to create our own trends too and we have core basics as to what we build our collections on and then we just add on the fashiony bits and layer it up a little."

There are 110 Karen Millen stores around the globe, from Reykjavik to Bahrain and now the European flagship store has opened at 73 Grafton Street, an auspicious address that commands a rent in excess of 1m a year. The interior is lavish, and it's unrecognisable as Principles, its previous incarnation.

The company has never believed in advertising as it has in having shops in the right places, Millen says. "We're in key positions in major cities in countries around the world and people can't help see what we do and if they like it, they'll buy us."

It's important to note her use of the words 'we' and 'us' here. Karen Millen, the person is not the same as Karen Millen the brand.

Although she started the company in 1981, alongside businessman Kevin Stanford, it was acquired in 2004 by Mosaic Fashion, which also owns the Oasis and Coast brands.

Millen's official title is now creative consultant and although she remains heavily involved in the business, the acquisition has allowed her to take a step back, something she admits she never thought she would do. Does she still feel a thrill when she sees someone walking down the street carrying a Karen Millen bag?

"Well, I guess you get used to it in a way.

That sounds sort of arrogant perhaps, but it's more seeing your name above the shopf To me, now it's a brand. I don't look on it personally. It's a brand that we built and there are a lot of people behind it, " she says. But, she adds, she is always proud to see people wearing Karen Millen clothes and can always identify when someone is wearing one of their pieces.

Millen herself is a chicly dressed, diminutive, blonde mother of three. In the early days of the company, she was the in-house model, as well as the designer and a lot of the clothes she created were based on how good she felt in them, as well as being a reflection of how she herself dressed at the time. This evolved as more people joined the team and now she describes the quintessential Karen Millen woman as being "energetic, very aware of herself and pretty cosmopolitan".

The clothes are structured, strong on tailoring and not age-specific. Is it aimed at the more sophisticated woman? Millen thinks about this before answering. "I think a lot of it depends on style and how you put things together because again, you can pull out a real sophisticated look if you want to; then some of our younger customers can put some leggings with it or a funky handbag and it can be quite fun."

She says she never really looks at other stores as competitors. Reiss for example, might have a similar price point but its looks are very different. Tailoring and attention to detail, the Karen Millen strengths, mean the clothes don't have the in-built obsolescence of other high-street offerings, she believes.

Again, the fact that the label doesn't slavishly follow fashion's whimsy works in its favour. "It's not seasonal as such, " she reiterates. "We do have pieces that people will come up to me and say 'I've got one of your old pieces from years back'. Unless it's a cotton shirt, but certainly with the tailoring, things are meant to last. Many of the clothes are dryclean only, which really helps, but even our knitwear is very good."

However, Karen Millen clothes are not for every woman. The label has always been known for its form-fitting cut and currently only goes up to a size 14. The reasoning behind this she explains thus: "Our shops were smaller for a start and they are beginning to get bigger but you can only fit so many things on a rail and something has to give one way or another. If we introduced another size then you're limiting the collection that you want to put out there so you've got to decide which way is going to be more beneficial."

They are planning, however, to introduce a size 16, a move which will definitely open up the market significantly. "Our body shapes are changing all the time; we're a lot taller than we used to be and being taller, you tend to be a bit broader." And fatter too? "Wellf probably, " she agrees, before bringing the conversation back to a more business-like, less controversial footing. "You can never stand still and think you've got to that level and that that's going to be okay, because it's not. It's quite a ferocious business and changing very quickly, and you've got to be up there on the ball and ready to change with them and listen to feedback. There's a lot to be learnt from your customers."

Joining the Mosaic group has opened up a lot of professional doors for the company and, on a personal level, has freed up a great deal of Millen's time, allowing her to spend more time with her three children, (aged 16, 14 and nine). They're proud of their famous mother but they're really grounded, she says.

Of the three, Jake, the youngest, is the most visually inclined. He moves furniture around the house as she also did as a child in her mum's home. Football, specifically supporting Arsenal is a unifying family activity but Millen's real love is for interior design. She has a home set on five acres in a village in Kent, a London house and is in the process of buying a place on the west coast of Majorca, spending any free time going to antique fairs and art exhibitions and picking up bits and pieces on her travels around the world. Doing up her homes is an extension of the fashion thing, she says, but she doesn't think her interiors are an extension of Karen Millen brand.

"They're a mix of contemporary and classic, " she explains. "Lots of black and white and lots of textures, which is similar to Karen Millen but Karen Millen in terms of clothing is more colourful, I guess, which doesn't reflect in my interiors at all. They're much more neutral." She says she's ready to absorb other things now but although she's been approached to get involved in some large-scale interior-design projects, it's not something she wants to take on at this stage.

"I'm not an interior designer, I don't have the qualifications, although I'm sure I'm capable of doing it, " she says. "I think I'd rather start smaller than that and see how it goes. But that's the great thing. I'm now at at stage in my life where there are so many opportunities that can come my way. I just want to wait and see what grabs me and what feels right." And that could eventually involve a move away from the fashion world. "One day, when I'm older and not whizzing around so much, painting or writing is something I'd quite get into.

"The reason I'm buying a place in Majorca . . . well there's a certain place on the west coast that just beautiful; it's an old part of the island. There's just something about it when you go there. It's very peaceful and it makes you want to be creative in terms of painting and drawing. It just has this air about it that's quite special. Maybe once I get my place there, I'll settle down and start painting."

MY FASHIONABLE LIFE BY KAREN MILLEN

On her favourite designers

There are lots, actually. There's not actually one particular designer that I follow. I've got to the stage in my life where I know what suits me, I know what I can get away with and what I can't. So I tend to go for things that suit, rather than because they're 'in' at the moment. I like Lanvin, Chloe, some Stella McCartney pieces, but it's a real mixed bag

On handbags

More than clothes at the moment, I like handbags. I have a Prada one with me today. I just keep buying them and you never use them all, it's terrible, but I look at them as pieces of art because they're so beautiful

On having a critical eye

Sometimes you look at people and think that they don't care about how they look and I find that a bit frustrating. A bit untidy. . bad shoes. . or just not making the effort to look smart. I suppose I've always like nice things, to be in a nice place and to be surrounded by beautiful people. That sounds terrible!

On current fashion trends

All of these bigger shapes that are coming through . . . they look good on the catwalk but really, at the end of the day, how many people can wear it?

Me included, being short. . But there's no one thing at the moment that makes me feel 'Ugh'. Even the leggings coming back . . . the funny thing with that was that I was there the first time round so I quite like it. In fact, I've worn them!