This was Princess Diana interviewed by Martin Bashir for Panorama in November 1995, less than two years before she died - after her separation from Prince Charles but before their final divorce.

It was vintage Diana, captivating television, a media master and victim walking her familiar line between cynicism, passion and restraint.

She casually coined soundbites ("I'd like to be a queen of people's hearts") that would posthumously define her, and she fired shots at her husband ("There were three of us in this marriage, so it was a bit crowded").

She spoke of bulimia and depression and self-harm, her puppy-wide, dark-rimmed eyes peering from below her extraordinary hair.

She spoke about the media. "I never know where a lens is going to be," she said. "A normal day [I] would be followed by four cars. There was a relationship [with the media] which worked before, but now I can't tolerate it because it's become abusive and it's harassment."

Shortly before midnight on Saturday, August 30, 1997, Diana was involved in a high-speed accident in the Place de L'Alma underpass in central Paris, as her car fled a fleet of pursuing paparazzi.

After two hours of emergency surgery she was declared dead, along with her new boyfriend Dodi Fayed and the driver, Henri Paul, who was drunk, and whom a 2008 inquest ruled was to blame, along with the photographers.

And there the story did not end.

An estimated 2.5 billion people watched her funeral at Westminster Abbey five days later. This, the 20th anniversary, has seen a blizzard of publicity, documentaries, books and interviews, magazine and newspaper special editions, across the world.

Somehow, still, we are captivated by the story of a troubled princess who left behind two traumatised boys and - arguably - changed the way royalty, celebrity and humanitarianism work.

A travel sickness bag is mandatory for much of the recent coverage. Even the most fervent Diana fan might choke on the Mail on Sunday's declaration last weekend that Diana "swept away an old, accepted order of protocols and politenesses and ushered in a new era of compassion and liberalism". Paragraphs later, the tabloid slavered over her "sculpted curves enhanced by a new wardrobe of swimwear" in the month before her death, an editorial position somewhere between lechery and butchery.

Plus ca change.

Her sons, Princes Harry and William, are still furious with the media, and as their role in the daily affairs of the royal family continues to grow, that fury must increasingly affect the Windsors' media strategy.

In the documentary 7 Days, which is due to screen on the BBC on Sunday, Harry says, "I think one of the hardest things to come to terms with is the fact that the people who chased her into the tunnel were the same people who took the photographs of her while she was still dying on the back seat of the car".

William recalls his mother was deeply distressed in the years before her death after run-ins with photographers who waited "like a pack of dogs for her, chased her, harassed her, called her names, spat at her, tried to get a reaction to get that photograph of her lashing out, get her upset".

In another recent documentary William said most of the times he saw his mother cry "was to do with press intrusion."

"One lesson I've learned is you never let them in too far because it's very difficult to get them back out again. You've got to maintain a barrier and a boundary. If both sides cross it a lot of pain and problems can come because of it."

He was obliquely referring to his mother's relationship with the media: she courted journalists and confided in them, trying to make them allies in her fight against the rest of her family. She deliberately exploited her fame to push causes. She told one interviewer she "felt compelled to perform".

The scene of the car crash in Paris. Photo: AP

In her children, compulsion has become repulsion.

One year on from Diana's death, the BBC's Nick Higham wrote "the public needed someone to blame [and] the media was the answer".

"The red-top tabloids were shocked by the public reactions. The result was a bout of media soul-searching and promises to do better."

The paparazzi did indeed back off - but they didn't go away. They sought other targets, mostly. Photographers and camera crews stayed clear of the royal children, begrudgingly.

Reporters still pried: a tabloid ruined the boys' plans for a surprise 50th birthday party for their father, for example. And the entire phone hacking saga was exposed when, on the advice of a TV reporter friend to Prince William, the palace set police to investigate whether a tabloid journalist had accessed William's voicemail for a string of royal scoops.

When it came to photos, foreign outlets filled the void: spicy (Harry cavorting in Vegas) and prurient (Kate Middleton sunbathing topless).

The latter case caused the royals to snap, breaking their usual silent-in-public, complain-to-editors-in-private strategy. William and Kate sued six people over the photos, which were published in two French magazines in 2012. In a statement read out to the court, Prince William said the photos were "all the more painful" in light of his mother's death and the harassment she had experienced.

The verdict is due in September, and could set a precedent for celebrity paps in Europe - one way or another.

But anyone who tries to argue that Diana's death doused the fires of celebrity-obsessed journalism hasn't looked at journalism lately.

And recently Hollywood has developed monarch fever: HBO's Elizabeth I, The CW's Reign, E!'s The Royals, Showtime's The Tudors, PBS' Victoria, and Starz's The White Queen, not to mention Netflix's The Crown, which promises to catch up with Diana in season 3.

Beyond the media, Diana could lay claim to a deliberate, and successful, recasting of modern royalty. There are some who look at the Queen's cameo in the 2012 Olympics opening ceremony, and see Diana's ghostly hand pushing her out of the helicopter.

Andrew Morton, author of the scandalous (and secretly Diana-assisted) 1992 biography of the princess, told CBC radio earlier this month that Diana's "is very much a living legacy with her children".

"She's kind of overshadowed or shadowed the lives of both boys, and in that sense as well, she's always been present," he said.

Diana explicitly intended this. She told Bashir the royals needed to change their relationship with the public, to "walk hand-in-hand as opposed to be[ing] so distant", and she wanted to achieve that through William and Harry.

"I take them round homelessness projects, I've taken [them] to people dying of AIDS, albeit I told them it was cancer ??? I want them to have an understanding of people's emotions, people insecurities, people's distress and people's hopes and dreams."

Charles Spencer, Diana's younger brother, told BBC radio last month that part of Diana's legacy was "she has left behind this image of what royalty can be and what it needn't be".

In his eulogy at her funeral he pledged to guide her sons "so their souls can sing openly ?- not immersed by duty and tradition", and he now believes "it's worked out very well - Diana was in their life long enough for them to receive an enormous amount of her values and warmth and humanity and I think people see that."

The wider royal family also realised they had to change after Diana's death.

On the eve of Diana's funeral the Queen told the nation, "I for one believe that there are lessons to be drawn from her life and from the extraordinary and moving reaction to her death".

Floral tributes to Diana outside London's Kensington Palace in 1997. Photo: AP

She was admitting the royals had badly mismanaged their response in the moment. Diana's death was the gravest royal crisis since the abdication. They had made a terrible mistake by holing up in Balmoral in Scotland - protecting William and Harry, it was later claimed, though this is hard to square with the decision to put the boys behind their mother, parading through the streets of London in Diana's funeral procession.

Royal biographer Penny Junor told Radio 4 documentary A Royal Recovery, "the whole family was in danger. The minute Prince Charles heard Diana had been killed his first words were 'They are going to blame me'."

One of the Queen's most trusted former advisers, Mary Francis, told the London Telegraph the royal family had feared "calls for some kind of republican action".

The narrative that Diana changed the Windsors is not universally accepted. According to some palace watchers, the royal family was modernising regardless. It had a discussion group made up of senior members of the family, dubbed the "Way Ahead Group". They had made significant moves reflecting modern times: the Queen had started paying tax and she funded the repair of Windsor Castle in 1992 out of her own purse. They had brought in an accountant to straighten up the royal finances, and had cut the number of family members whose lives were paid for directly from the annual government grant known as the Civil List. Most heart-wrenchingly for the Queen, the Royal Yacht Britannia had been scrapped, and she had not asked for a replacement.

Author Monica Ali also doesn't have any truck with the theory that Diana changed the monarchy. "The monarchy is much as it was pre-Diana," she wrote recently. "Diana's life and death didn't reinvigorate the monarchy, it reignited our fascination with it."

Outside palace walls, Diana's charity work has stuck with the next generation. Harry, William and Kate have founded Heads Together, a campaign that aims to "end the stigma and change the conversation on mental health". They continue working for many of the charities their mother introduced them to.

But they have big boots to fill. And some argue that Diana's true successors are not William and Harry, but Bono and Angelina Jolie.

The BBC's Jackie Long wrote that Diana "made giving glamorous".

"She embodied the caring '90s but still hung on to some of the style-obsessed '80s. Princess Anne had trudged around the Third World doing charity work for years - she just didn't do it so beautifully."

Diana held hands with AIDS patients, wandered dangerous London streets to meet the homeless, travelled to African and Bosnian battlefields sown with land mines.

Harry told a documentary this year "she had the ability to literally change the mindset of millions of people". She is widely credited with the success of an international landmine ban treaty, signed months after her death.

Diana talks to amputees who lost limbs to land mines, in Angola in 1997. Photo: AP

For Diana, it was where she felt she belonged. She told Martin Bashir, "I found myself being more and more involved with people who were rejected by society - with, I'd say, drug addicts, alcoholism, battered this, battered that - and I found an affinity there.

"I respected very much the honesty I found on that level with people I met, because in hospices, for instance, when people are dying they're much more open and more vulnerable, and much more real than other people."

Journalist Andrew Marr wrote that Diana's life and death coincided with a shift in Britain. The country left behind the greed-is-good '80s, and was becoming "more compassionate, more informal and more image-conscious", he said.

Whether she was setting the pace or sensing the trend, Diana had been at the forefront. Her death "revived the culture of public sentiment", Marr said.

Andrew Morton agrees, saying "Britain's stiff upper lip brigade ended with the funeral. And we have more of a trembling lower lip."

"I think that we've become a more expressive nation, a more touchy, feely nation than we were perhaps 30 or 40 years ago. And I think that Diana is a symbol of that."

Earl Spencer, Princes William and Harry, and Prince Charles, at Diana's funeral.

Author Monica Ali wrote in 2011 that Diana has frequently been blamed for "our newfound emotional incontinence".

"It's likely that the way she chose to speak out did accelerate a trend for greater openness, that her death had an impact on the ersatz sense of community that surrounds certain tragedies," Ali said.

But she chooses to view it in a positive light. "For some people, Diana will always be the patron saint of the self-obsessed. I see her differently. I think she had a lasting influence on the public discourse, particularly in matters of mental health. When she spoke publicly about her bulimia, the effect was powerful.

"Speaking out instead of shrivelling up was not just a sign of wilfulness - but of her determination to direct her loss and suffering outwards. It was a mark of her strength of character; small wonder that millions of people instinctively responded to that."

Ali says Diana also fundamentally changed the world of charity.

She showed the way for the Madonna and Angelina Jolie, for George Clooney in Darfur and Bono in Washington DC. "Put simply, Diana made philanthropy sexy."

Not everyone agrees that Diana changed the world. Pulitzer-winning writer Anne Applebaum has called Diana's legacy "pea-sized". She wrote in Slate magazine that "the genuinely bizarre aspect of the all-consuming Dianamania that gripped Britain [after her death] is how slight a trace it has left behind. Actually, the royal family is pretty much the same, only quieter. From Diana, they learned that there is such a thing as too much publicity.

"One could argue that Diana's truest legacy is the screaming emotionalism of the British tabloids - except that it long pre-dates Diana, and in fact helped create her in the first place."

Telegraph columnist Simon Heffer also swam against the tide of sentiment. Ten years ago he wrote a column titled "Diana just another dead glamorous celebrity", railing against "the absurdities of the cult" that had grown up around her.

"Ludicrous ideas are voiced of her contribution to humanity," he said. "[Her death] showed just how unpleasant mass hysteria is. But worse, it revealed an increasingly ungrounded and shallow society that can attach such significance to such things."

He hoped the 10-year commemoration of Diana's death would be the last such public event, and "those who still feel the need to mourn will now be encouraged to do so privately".

Ten years later, he has been proven so, so wrong.

A grand family

Althorp Estate, the Spencers' ancestral home in the Midlands. Photo: Althorp Estate

It's often forgotten that the "people's princess" came from one of Britain's grandest families. But visitors to Althorp Estate, the Spencers' ancestral home in the Midlands, and the site for Diana's final resting place, will emerge under no illusions that she was a royal outsider - despite being the first Englishwoman to marry an heir in 300 years.

This is one of the country's grandest homes. Althorp is set in rolling English countryside (one of the first times that Charles met teenage Diana, he was visiting for a "shoot" on the grounds).

Its halls and rooms are lined with endless aristocratic portraits, dating back centuries. The house was built in the 16th century but a Bose speaker system here, a bedside thriller there betray the fact this is a living aristocratic home.

And some speak of its owner's anger. An exhibition enshrines the Earl Spencer's handwritten notes for the press statement he made on hearing of his older sister's death. There is a hash mark and he has added a second-thought paragraph, saying "I always believed the press would kill her in the end" and accusing every proprietor and editor who ever paid for an intrusive photo of having "blood on their hands today".

At the main house, the first room is floor-to-ceiling horse and hounds paintings. But in the next room is a different, modern work: contemporary artist Mitch Griffiths's Rehab. It shows a near-naked man in crucifix position, his addictions on display including a champagne bottle in a bucket marked with the blood-red logo of The Sun newspaper.

And upstairs, in a Tudor-era long room where ladies used to take their exercise when it rained, another Mitch Griffiths titled Britannia sits front and centre. It's a portrait of a haughty young woman in a short denim skirt, CCTV camera on her shoulder, police tape on her empty pram. She is the modern UK, and she's not there to be loved.

It is placed last in a series of oil paintings of the mistresses of King Charles II.

A guide tells me Earl Spencer wanted to imply they were "no better than she is".

Outside, a short walk away, you find the oval lake, at the centre of which is a round island, in the middle of which lies Diana's grave, concealed by clippered hedges. The message is Diana-esque. She is protected but on display, withdrawn but exposed.

Come see me. But don't get too close.