“While she was alive my mother never talked much about the past,” says Rory Green, one of Jackie Collins’s three daughters. “She had experienced so much pain that she wanted to preserve the happiness that she had found. ‘You’ve got to keep on keeping on,’ she told us, opting never to have therapy. So we knew the outline of the past, but we never knew the details until she died.”

It has been almost six years since her death, but the image of Jackie Collins still looms large in the public imagination: say her name and women of all ages will immediately call to mind unapologetic ambition, sexual decadence and lashings of leopard print. And it’s not just her image that prevails — her books continue to sell, and the iconic Lucky Santangelo titles have been picked up by Monumental Pictures’ Alison Owen — the producer of Suffragette and Lily Allen’s mother — who is looking at dramatizing the stories and streaming them (because “people would binge-watch the story the same as they binge-read the books”, Rory says). But as Lady Boss, a new documentary about Jackie’s larger-than-fiction life reveals, the Jackie Collins we knew was barely half the story.

The Collins sisters, 1977.

The documentary makes fabulous use of the extensive archive that Jackie kept throughout her life. Teen diaries filled with worries about feeling frumpy at parties in comparison with her older sister, Joan, an up-and-coming starlet, say; or an evening spent at a Hollywood house party with a twentysomething Marlon Brando. And a wealth of gleeful personal video footage featuring everyone from Roger Moore goofing around at family barbecues to Jackie doting on her baby daughters. Then there is the fact that she kept every cutting, every review, every profile her novels received, each one painstakingly scrapbooked by her. Given that she sold half a billion (yes, billion) books in more than 40 countries, this was surely no mean feat. So did her family know she was keeping this archive?

Yes and no, Rory says. “We guessed she was keeping a lot of something — she lived in a very large house by herself, and was obsessed with built-in storage. So we knew there was plenty hiding in those cupboards. But we never looked until after she died.”

The documentary came about as a result of conversations between Jackie’s daughters and the team at Passion Pictures and director Laura Fairrie, who had no idea such an archive existed. So how did the sisters feel about handing over so much material, including so much that was intensely personal? “She was, on a cellular level, a storyteller,” Rory says, adding that the sisters were united in agreement that their mother would want her story heard. “She wanted to tell her own story. She had started her autobiography.”

It has been almost six years since her death, but the image of Jackie Collins still looms large in the public imagination.

This sense of Jackie being the architect of her own story is clear in the film. It spares very little of her pain at the demise of her first marriage to a man who suffered from depression and addiction, and was ultimately an emotionally and physically abusive husband who ended up taking his own life. And it shows how very hard she worked, including, in the early days, “writing when stopped at traffic lights” while she was taking three small children to school in order to meet deadlines. But it also delves into her decision to maintain both a definitive look and a steely resolve once her career took off. Instead of tarnishing an iconic image, these insights only prove how much more there was to a woman who so many once saw as all surface and little substance.

“She left this material for a reason, and we feel this film has finally made her three-dimensional,” Rory says. And she’s right. Scenes from her books where well-known characters such as Lucky wrestle back control from overbearing and often abusive men read differently once you’ve seen diary excerpts describing Jackie’s pain following her first husband’s threats. And her almost predatory boss-bitch manner in interviews — the shoulder pads, the big hair, the wry smile — makes more sense when you rewatch clips of Clive James and his male contemporaries reviewing her disparagingly on late-night TV. “She’s nothing and she’ll always be nothing,” they snigger, apparently missing the point that while her prose might not have impressed them, she was a rare voice amplifying women’s desires, frustrations and ambitions in an industry still led by men. To have achieved what she did in a climate that was valuing her this little now seems all the more audacious.

She was a rare voice amplifying women’s desires, frustrations and ambitions in an industry still led by men.

Then there is her relationship with Joan, who is interviewed at length in the film. As the younger sister, Jackie watched with both envy and admiration as Joan took on Hollywood in the 1950s, mixing with the likes of James Dean and Paul Newman. She then had her own confidence almost obliterated when she tried her hand at acting, only to have her apparently subpar looks reviewed more than her talent. “Her scrapbooks show that the papers would call her ‘new girl on the scene’, then run through the measurements of her bust, her waist and her hips,” Rory says. “She found it so hurtful.”

However, what emerges is that these early years, and the extra time they gave her to be the observer before becoming the observed, were the rocket fuel for her career. After all, it was as a discreet presence at more than half a century of show-business soirées that Jackie was hardest at work. And when Joan’s career stalled, it was Jackie who was able to reboot it by writing the novels that provided her game-changing roles in the 1970s movies The Stud and The Bitch.

Jackie wrote the book, and her sister, Joan, starred in the movie.

The documentary dances impishly around the relationship between the sisters. One scene shows Joan explain — with apparent sincerity — that Jackie has been reincarnated as a fly that follows her around. But it also sees her welling up when describing some of their happiest times, as well as looking a little sheepish when she tries to skirt around any sisterly competitiveness regarding her trying her own hand at novel writing. Is this a true reflection of their relationship, I ask Rory. “Of course! Everybody refers back to that classic French and Saunders sketch — Lucky Bitches — with a sort of one-dimensionality. But this was a real relationship with real complexities. There was a huge devotion between the two of them, but there were seasons, as there are in real relationships. They were not caricatures.”

The caricature of the perma-glam Jackie Collins-at-work is also skewered. Rory describes her much-pilloried leopard-print look as their mother inhabiting something close to a drag persona. “We knew it meant she was going to work.” But as for her fans’ fantasies that she headed to her office in diamonds and Louboutins each morning? “We used to laugh, because she wore the same outfit of black trousers, black T-shirt and black shirt whenever she was writing. She even teased us for being fancy when we had our nails done! But when she turned herself into ‘Jackie Collins’ there was something almost magical about it.”

For myself, a huge Jackie Collins fan whose English teacher described her works as “lurid”, it wasn’t just the female characters’ lust for “absolute studs” that was life-changing — it was their lust for independence, for financial freedom and for speaking these desires out loud. While my school reading list was sorely lacking in female role models that suggested any of this might be possible for me, I always had Jackie — including a signed edition of one of her novels, in which she wrote in her famous looping handwriting, “Remember Alex, Girls can do anything”.

Jackie in 1969 as she attempted to find the six most beautiful pairs of legs for the cover of her new book, The Stud.

After university, I worked at her publishers, Simon & Schuster, in the early 2000s, where she was universally loved and admired. As Suzanne Baboneau, the managing director and Jackie’s line editor, told me: “She knew the value of a deadline, and always delivered a wonderfully clean manuscript.” It wasn’t just her professionalism that so endeared her to us all, but the fact that she still loved some of life’s most simple pleasures: we knew when Jackie was coming to town when someone had to hit M&S in Marble Arch for prawn sandwiches.

“It’s true!” Rory says. “There was almost nothing she loved as much as pottering around M&S buying knickers.”

What she clearly loved most of all, though, was her family. Rory tells me that she always had a second chair in her office, and if one of her daughters sneaked in to see her while she was writing, she would read an (edited!) excerpt, complete with voices, “just like when she did the voices in The Faraway Tree at bedtime”.

Jackie and her daughter Tiffany Lerman. In the early days, Jackie juggled her career with motherhood, writing even when stopped at traffic lights.

By the time of her death Jackie had six grandchildren, whom she adored and was adored by. Most of the family moved back to LA to be with her when she was diagnosed with stage 4 breast cancer, and Rory describes it as extraordinary that she was able to live “such a vibrant life” for a further six and a half years post-diagnosis — a feat particularly admirable given the fact that she had kept her cancer secret from almost everyone (including her sister, who she told much later). “She didn’t want to be pitied, she wanted to dwell on the good times. I thought of her when news of Helen McCrory’s death broke, for that reason,” Rory says.

Jackie died in 2015 at the age of 77, days after her final, carefully masterminded trip to the UK, which included meeting Joan for dinner at the Wolseley in Mayfair and a lively appearance on Loose Women. Of all her carefully crafted creations, perhaps the greatest character of them all was her own: Jackie Collins, best seller.

Alexandra Heminsley is the author of Some Body to Love