The death of Queen Elizabeth II marks a shift in the relationship between fashion and the British monarchy, with younger members of the royal family, notably Catherine, Princess of Wales, likely taking on a greater public role.

The late queen had a precise fashion formula - elegant coats, trim hats and square-heeled shoes shaped her familiar silhouette, as well as her handbag, which became a symbol of stability.

"The Queen was aware of how useful a tool style was to help convey her image as monarch," said Alicia Healey, who worked in the Queen's household for four years and has since written a book called "Wardrobe Wisdom from a Royal Lady's Maid: how to dress and take care of your clothes".

"I think, to a certain extent, her clothes were a uniform for her."

While the fashion choices of the new monarch, King Charles III and his wife Queen Consort Camilla, will inevitably attract attention, they are both in their seventies, meaning camera lenses will be focused more on Charles' children, William and Harry - and their wives.

That could see a shift in the royals' association with fashion from formal structures to more relatable - if restrained - styles.

With Harry and wife Meghan now based in California, William's wife Catherine, popularly known as Kate, is set to hold the public's sartorial gaze, recalling the era of William's late mother Diana when she was Princess of Wales.

"I think, really, people are interested in the younger members of the family and what they are wearing because they relate much more to us, to what we wear to parties or to work," said fashion critic and historian Suzy Menkes.

TRICKY FOR KATE

Styles worn by Kate, 40, have been known to spark buying frenzies. The polka dotted dress by Jenny Packham she wore in 2013 after the birth of eldest child Prince George subsequently sold out. It was seen as an homage to Diana, also photographed in polka dots when returning home with baby Prince William.

Kate's style is usually understated but when she dresses up it generates excitement, fashion experts say.

"Whenever the future queen wears something that is a little bit sexy and glamorous, people get very excited about it because Kate isn't really someone who dresses like that," said Menkes, who describes her style as casual but smart.

"It's interesting to see how that's going to change and whether she is going to go up a notch and look slightly more glamorous," she said.

But doing so could be at odds with King Charles' sustainability messaging.

"Charles' sustainability push calls for a little bit more conscientious fashion," said Jennifer Castro, a West Palm, Florida-based digital marketer, whose fashion blog RoyalStyleWatch has more than 67,000 Instagram followers.

"Charles is someone that has had the same camel coat for 25 years - he's very much about purchasing quality items that will last," Castro said.

NEVER MISSED THE MARK

Gerald Bodmer has lost count of the glossy Launer handbags Queen Elizabeth II bought from his company through her seven-decade reign, but the classic, hand-stitched accessories have been part of her wardrobe since the 1950s and 60s.

He estimates she ordered around a dozen over the past 40 years, sticking to only a handful of models, such as the top-handled Traviata, in a subtle trapezoid shape, which sells for around 2,090 pounds ($2,390).

In her last public photo, with Britain's new Prime Minister Liz Truss, she carried a pre-1980s Launer bag, while the creamy vanilla-coloured bespoke Lisa hybrid model she sported at William and Kate's wedding in 2011 sparked such a flurry of interest the company's website crashed, according to the label.

For many, the accessory will be forever linked to the Queen.

"I never noticed any handbags except those worn by Her Majesty," said Menkes. "Other people, of course, must have handbags, but they haven’t quite entered my soul."

The Queen set a high bar when it came to striking the right tone, said Elizabeth Holmes, author of 'HRH: So Many Thoughts on Royal Style'.

"It's incredibly savvy of her to have recognised the power of clothes and harness that to promote sort of the monarchy and support her royal duties," Holmes said.

"There was never a moment where the Queen missed the mark - where she was dressed inappropriately, where her wardrobe failed in some way. And for 70 years to be that consistent? I think we take it for granted."