The exhibition Diana: Her Fashion Story showcases the late princess’s dresses and outfits.
The exhibition Diana: Her Fashion Story showcases the late princess’s dresses and outfits. Photograph: Xinhua/REX/Shutterstock

An exhibition of Princess Diana’s old dresses, at Kensington Palace, is the inaugural event in the 20th anniversary of her death, aged 36, in 1997. Paying up to £16.50 a ticket, visitors are invited to “celebrate the life of Diana, Princess of Wales”, by inspecting 25 outfits that encapsulate her journey, it is promised, from “the demure, romantic outfits of her first public appearances, to the glamour, elegance and confidence of her later life”.

To judge by glowing press previews, the clothes – accompanied by photographs of Diana in them – have none of that dismal, faintly charity shop look that even the most fantastic dresses can acquire, once their original owner is dead and they have been draped over a dummy.

Doubling as a wonderful pretext for newspapers to re-use huge photographs of the princess, the exhibition – edited to suggest heroic resistance to the fashion crimes of the 1980s – is said to show how Diana expertly updated ancient royal traditions, consciously deployed clothing to manage her image and inspired mass imitation, before emerging, in pastel suits, as the acme of restrained good taste.

Anyone who was around at the time will know that a completely different, equally true, and certainly as captivating fashion story could have been told in 25 quite different garments. These might include, say, red leather trousers, bow ties, Lycra, bomber jackets, leopard-print, cartoon sailor collars, white tights, military frogging, deckchair stripes, blazers, bikinis, giant checks and more of the massive, clownishly shouldered jackets that Diana would accessorise – often to 1980s acclaim – with panto tricorns, pillboxes the size of cake tins.

Much more memorable, to my mind, than any of the Demarchelier monochrome portraits was a whimsical session in which Diana, wearing boots and stretch breeches, constructed with fellow taste-maker, the late Lord Snowdon, a faux-pastoral, wicker-strewn picnic scene, accessorised with a pony, her husband and sons.

She was collaborating at the time, with superb recklessness – or courage – on a book, Andrew Morton’s Diana: Her True Story, which sprung on an unsuspecting nation and its ruling family a heartrending tale of her misery and betrayal at the hands of Prince Charles. Asked if she was involved, she would insist “absolutely not”.

Also arguably more iconic than the black velvet dress in which Diana danced with John Travolta would be the suit in which she pleaded with a rapt audience for “time and space”, or another businesslike outfit in which, her eyes ringed in kohl, she would give her jaw-dropping interview to Panorama’s Martin Bashir, unknown even to her private secretary. The point of that plain outfit being, precisely, to prove that she was not a clothes horse; rather, she portrayed herself as Chelsea Harbour’s answer to Walter Bagehot, a truth-teller destined to save the royal family from itself, and in particular, from the arrival of Charles III and his fancy woman. As for herself, Diana modestly vouchsafed, in a programme that would duly cost her HRH, she wished only to be, “a queen in people’s hearts”.

Supposing exhibitions of designer clothing are the ideal way to command respect for a public figure, the nature of Diana’s legacy is particularly vulnerable – as memories fade of her consistently astonishing behaviour – to being lost under a heap of jewelled Versace and fashion writer superlatives. Where the interest in most celebrated scraps of historic clothing, from the Brontës’ tiny dresses to Mrs Thatcher’s ghastly suits, arises from knowledge of their wearer’s achievements, the Diana exhibition suggests – as some of her detractors will think, accurately – that looking lovely in different clothes was, as with the current range of princesses, pretty much her life’s work.

Jacques Azagury, a designer whose clothes she wore, says, by way of a compliment, “she was excited to see what was new, but she already knew how she wanted to look”. If that, along with her attention to detail, suggests something uniquely skilful behind Diana’s various dressings up and photoshoots, it is surely not an art that puts her, in terms of cultural significance considered 20 years on, much ahead of Kate Moss.

In fact, being drawn so narrowly from the category Occasion Wear, the costumes and photographs could scarcely have been better chosen to overlay memories of the surge of royal-blaming that Diana’s death inspired in 1997 – of her own reinvention as a global charity envoy and amateur healer, of her appointment as feminist heroine as well as tabloid goddess and, above all, of her magnificent achievements as the royal family’s incorrigible, lead tormentor.

The curator of her clothes show styles her a fashion icon,“stepping into that same sort of space as an Audrey Hepburn or Jackie Kennedy”. Which is also to say, for younger visitors, that the exhibition could even be seen to reduce Diana to the big-spending simpleton who was castigated in Anthony O’Hear’s revisionist essay of 1998, as shallow and self-obsessed.

In 2007, the last big anniversary year, many assessments of the princess’s contribution, including Tina Brown’s The Diana Chronicles, still credited her with a lasting Diana Effect: a modernising, emotionally literate tendency for which both crown and country should be grateful. Although early calls for her to be canonised had by then subsided, Tony Blair assured Tina Brown: “Diana taught us a new way to be British.” If that manages to be both bland and hyperbolic, it was definitely unthinkable, before Diana, that a royal would, say, disclose her postnatal depression, self-harming or bulimia, or the names her in-laws called her on that account: “Diana’s unstable and Diana’s mentally unbalanced”.

That it is impossible to imagine her successors going in for comparable sharing only underlines, on the other hand, how rapidly the royal family restored its factory settings – absorbing, along the way, the woman who prompted Diana into vengeful activity.

In fact, it may not greatly disturb Prince Charles, with his scheme to promote Camilla to queen, if, far from recalling Diana’s chosen career in scandalous non-compliance, this year’s anniversary highlights are the agreeable clothes show, celebrations (but at Althorp) of the Diana Awards for children, and a new monument, commissioned by her sons.

Kensington Palace announced last month that “the time is right to recognise her positive impact in the UK and around the world with a permanent statue”. A Guardian colleague has already expressed the hope, probably vainly, that the art work will not be “a dire chunk of conservative kitsch”, but something abstract, contemporary. “How about,” wrote Jonathan Jones, “a work by Yinka Shonibare that explores Britain’s colonial history?” But that, surely, is more the preserve of Diana’s ex-husband and her sons, what with their noted enthusiasm for Africa and tribal fancy dress.

Anyone old enough to have gawked at Diana’s progress, from uneducated 19-year-old target of a secretive thirtysomething, into a wildly competitive, ungovernable celebrity, will surely agree that her achievements merit something more personal, especially considering the steadily declining quality of royal entertainment. HRH, in gigantic gold letters?