The exhibition’s final room holds a number of the La Femme Dresses Diana auctioned off for charity, at her son William’s suggestion, shortly before her death in 1997. They include a green silk velvet evening dress by Catherine Walker, which she wore for a Vanity Fair photoshoot with Mario Testino, and a beautiful ‘dignified showstopper’ by the same designer, in grey silk satin with imitation pearl embroidery, which she wore to a state dinner with the King of Malaysia in 1992.


‘It was widely reported that the auction was a symbolic event, a way for Diana to close a chapter on her royal life and embark on a new one. Just a few months later, she died,’ says Eleri.’


What, in Eleri’s opinion, are the exhibition’s stand-out pieces?


‘If I had to choose two dresses, her “debs” gown [a flouncy Regamus dress she wore to a ball as a teenager] would be one of them. It’s very of its time, very frilly, very lacy. There’s a real innocence about it.


‘The other would be totally different: the black, halter-neck Catherine Walker dress she wore for the Mario Testino photoshoot just before she died. It’s got such a beautiful, streamlined silhouette and is so simple and understated — yet very difficult to pull off.


‘I think the contrast shows just how far Diana had come in her short but incredible life.’Catherine Walker, 1986


Dubbed ‘my mermaid dress’ by Diana, every inch of this dramatic gown is embellished with sequins and was designed to shimmer under the flash-bulbs that followed her every move.


Typical of her so-called Dynasty phase — after the dramatic shoulder pads and lavish fabrics favoured in the glamorous TV show — Walker’s evening dress was beautifully embroidered by the legendary textile designer Jakob Schlaepfer and it clung to every curve.


With its swooping neckline, structured shoulders and ruched detailing — all of which highlighted her slender waist — it was an outfit designed to show off Diana, the dazzlingly desirable woman.


Only later did the reason for that new-found body confidence become clear. In 1986, when she first wore it during an official visit to Vienna, the 25-year-old princess had just embarked on an affair with her Cavalry riding instructor, James Hewitt, after her husband had reignited his long-term relationship with Camilla Parker-Bowles.


Flush with infatuation for the dashing Lothario, who would later betray her in a tell-all book, sexuality oozed from every pore.


‘It’s a sexy, figure-hugging piece,’ says the Mail’s style editor Dinah van Tulleken. ‘All-over sequinned fabrics are not the most forgiving, but Diana didn’t need to worry.’


The glittering dress was first snapped up at auction by a mystery woman from Florida, who sold it on in 2013 for £90,000.


Catherine Walker, 1987


It’s the Disney-esque fairytale gown every little girl dreams of wearing, complete with elegant sleeves and a full, flowing ballgown skirt. In delicate rose pink, of course.


And yet, as pink and princessy as this Catherine Walker dress is, Diana looks far from powerless or fragile in it.


Its white, raw silk collar drops seductively from the shoulders to display an almost daring amount of decolletage, while its matching cuffs mirror the buttons on the structured waist to hint cheekily at a man’s classic tuxedo while accentuating her long, lean torso.


The grandeur of the satin evening gown — sold in 1997 for £20,000 — was entirely deliberate as it was made for the princess to wear for an official portrait by Terence Donovan alongside her husband in 1987.


It was a delicate moment in the couple’s marriage: both had by now taken other lovers and Diana, although never entirely relinquishing the torch she carried for her husband, was also beginning to find an inner strength she never knew she possessed.


No longer would ‘Shy Di’ play second fiddle to Charles; this was a woman who knew her own worth — and wanted a dress that would hold its own next to her husband’s elaborate ceremonial uniform.


Diana loved it so much that she wore it in public on four separate occasions, the first time being for a night out at the Berlin Opera House during an official visit to Germany in November 1987 (main picture). The distance between her and Charles was very much in evidence as they walked down the red carpet, several feet apart.


As if to emphasise the gulf, Diana held her hands behind her back and dipped her head coyly, showing off the elegance of her shoulders, as well as her trademark pearl necklace and earrings.


Emanuel, 1981


Diana’s memorable ‘engagement portrait’ was, in truth, an accident of fate. The picture, taken by the late Lord Snowdon, was originally commissioned as part of a Vogue feature on ‘upcoming beauty’, and had been facilitated by her elder sisters, Sarah and Jane, who had both worked for the title.


Diana walked into the shoot and, faced with a rail of clothes, made a beeline for this blouse with its distinctive satin neck ribbon. It was made by the then-unknown young husband and wife design duo, David and Elizabeth Emanuel.


Fortuitously for Vogue — and the Emanuels — the timing of the publication coincided with the announcement of Lady Diana Spencer’s engagement to the Prince of Wales.


In a matter of days, the young aristocrat’s comfortable world had exploded, making her choice of the delicate shell-pink blouse, which emphasised her fragile beauty, all the more poignant.


Quickly dubbed ‘Lady Di’ blouses as the nation fell in love with their new princess-to-be, pie-crust collars and pussy-bows became the height of fashion, and thousands of imitations promptly sold out on the High Street.


Diana loved its makers so much that she famously asked the Emanuels to design her wedding dress. And she remained loyal to them, even after an over-sized green and black tweed coat they made for her was dubbed ‘the horse blanket’ by the international media.


Mail style editor Dinah van Tulleken, says Diana’s iconic blouse would still be the height of fashion today.


‘Statement collars and pussy-bow details are back for 2017, and this eye-catching design could be straight off the Gucci catwalk,’ she says.


Atelier Versace, 1997


As Princess of Wales, Diana had adopted the royal tradition of wearing clothes by British designers, and throughout her time as a working princess she stuck faithfully to a trusted coterie of upper-crust couturiers, such as Bruce Oldfield and David Sassoon.


But following her separation from Prince Charles, Diana decided to experiment with international labels. It was a small but significant sign of her growing independence.


As she once said of her introduction to royal dressing: ‘I couldn’t have Elegant strapless gown with crystal detail by La Femme 19636 Prom Dresses clothes because it wouldn’t have been practical for the job, but I had to have clothes that had to last all day long, sensible colours and sensible neckline and skirt length.’

Elegant strapless gown with crystal detail by La Femme 19636 Prom Dresses


Now, controversially stripped of her HRH post-divorce, Diana rose like a phoenix from the ashes of her royal life in this body-skimming, embellished ice-blue number by Italian designer Gianni Versace, which cleverly leaves just the right amount of flesh on show. Made from elaborate beaded silk, it’s a stunning example of the new, sexually confident princess — as this 1997 cover photo for Harper’s Bazaar, shot by fashion favourite Patrick Demarchelier shows.


‘The simplicity of this image, with its understated hair and make-up and lack of jewellery, means it hasn’t dated. And it’s a stunning dress that wouldn’t look out of place on the catwalks today,’ says the Mail’s style editor Dinah van Tulleken.


‘Your eye is drawn to the low-cut neckline which is embellished with turquoise and gold studs, pyramids and faceted glass. It’s a silk dress with silk lining — exquisite and now iconic. A one-of-a-kind haute-couture piece.’


Catherine Walker, 1987


Diana loved going to the movies — Hollywood blockbusters and rom-coms were always favourites — and would often visit her local cinema on Kensington High Street disguised with a scarf and an over-sized pair of glasses.


Sometimes she also took fashion inspiration from the movies. For this strapless dress, by designer Catherine Walker, she looked to Grace Kelly’s gown in Alfred Hitchcock’s 1955 classic To Catch A Thief.


Made from the palest of blue silk chiffon, the floor-length bandeau gown and matching scarf were premiered, appropriately, at the Cannes Film Festival of 1987 then worn again two years later at a performance of Miss Saigon in London.


Its flattering draped and tucked bodice highlighted the la femme prom dresses ’s long torso and tiny waist and, by using a clever crossover to pull her in at her thinnest point, Walker also managed to exaggerate her modest bust.


Diana showed her knack for old-school Hollywood glamour by including a fabulously elegant scarf and shoulder-dusting sapphire earrings, completing the look with matching satin heels.