FAR from being practically perfect in every way, Julie Andrews once put a bumper sticker on her car which said: “Mary Poppins Is A Junkie.”

It was a jokey, failed bid to banish the sugary-sweet reputation she had been stuck with because of the role — but if she had actually told the truth behind the classic movie, she might have succeeded.

Dick Van Dyke and Julie Andrews in 1964 Disney classic Mary Poppins Credit: Cover Images

Julie Andrews wanted to banish the sugary-sweet reputation she had after Mary Poppins Credit: Getty – Contributor

The actress shocked the children in the film with her swearing and by smoking on set — while co-star Dick Van Dyke was an alcoholic who struggled with suicidal thoughts even as he danced around singing Chim Chim Cher-ee.

Meanwhile, the writer of the original Poppins novels was at war with the film’s producer Walt Disney, obsessed with the occult, dogged by claims of racism and accused of ruining the life of her adoptive son.

Later Matthew Garber, who played the joyous young Michael Banks in the 1964 box-office smash, died tragically at the age of 21 after contracting hepatitis in India.

Despite it all, the 1964 film remains a beloved family favourite — and a sequel, Mary Poppins Returns, opens on December 21 starring Emily Blunt as the carpet bag-toting nanny.

The latest trailer for Disney’s Mary Poppins Returns starring Emily Blunt has been released showing off the wondrous world of magic

The long-awaited Mary Poppins sequel stars Emily Blunt as the magical nanny Credit: 3

Karen Dotrice, now 63, who played young Jane Banks, at the Mary Poppins Returns premiere Credit: Getty Images – Getty

Karen Dotrice, now 63, who played young Jane Banks in the first film, is not surprised at its treasured status. She says that despite what went on backstage, the whole cast realised they were involved in something special.

She said: “We started to feel like one big family and that we were all making something fun together that felt really magical.”

But she still remembers her shock as an eight-year-old at seeing Julie Andrews, then 28, in full prim Edwardian nanny get-up — with a cigarette and exchanging blue language with the crew.

Karen added: “There was swearing. Julie Andrews was smoking on set. It was a very real 1960s set, I can tell you. They were polite around minors to begin with, but that soon ended.”

On set Andrews shocked child actors Karen Dotrice and Matthew Garber with her swearing Credit: Getty – Contributor

Dick Van Dyke has admitted that he was an alcoholic at the time playing chimney sweep Bert, and would turn up for shoots suffering from the night before.

The American, who has a cameo in the new film, said: “I would go to work with terrible hangovers, which if you’re dancing is really hard.”

Van Dyke, 37 at the time of filming and now 92, also revealed booze led him into dark bouts of depression, revealing: “I was in deep trouble, you get suicidal and think you just can’t go on.”

However, he does not blame booze for the most infamous part of his performance, the Cockney voice which still tops lists as the worst accent in the history of cinema.

Dick Van Dyke does cockney in Mary Poppins

Dick Van Dyke has admitted he was struggling with a drink problem during the time of filming Credit: 1968 Ron Galella

Van Dyke, now 92, pictured with Karen Dotrice and Julie Andrews Credit: Rex Features

For that, he blames, among others, Julie Andrews.

He once explained: “I was working with a cast of almost all Brits and neither Julie nor anyone else ever said, ‘You know, you ought to work on that accent’.”

Meanwhile, he was well aware that on the sidelines, PL Travers — the writer of the Poppins books — was not happy with the casting of either himself or his co-star.

He has said: “She hated Julie and she hated me.”

Author P.L. Travers (pictured with Andrews and Disney) was not happy with the finished film

In fact — as described in the 2013 film about the making of the movie, Saving Mr Banks — Pamela Travers hated pretty much everything to do with the adaptation, which went on to win five Oscars.

For 20 years she had sent Walt Disney packing every time he had tried to buy the rights to her stories — and when she finally gave in, she regretted it bitterly.

Her own Poppins character, who first appeared in a novel in 1934, was cold, intimidating and given to making pronouncements with “a superior sniff”.

And yet here the nanny was, sweet, smiling, lovey-dovey and dancing with animated penguins. She saw it as an insult.

Travers refused to sell the rights to Disney for 20 years and then banned him from making a sequel

After the premiere, Travers told Walt Disney, “All the animation has to go,” not realising it was too late. The mogul put her right, saying: “Pamela, the boat has sailed.”

Travers got her revenge by refusing him permission to make a sequel — even reportedly specifying in her will that “no Americans shall ever be granted permission to work on a Poppins project ever again”.

She died in 1996 — and Disney is now behind the new film, with the approval of her estate.

Ironically, the movie was a passion for Walt and the books a passion for Travers for the same reason — troubled childhoods.

Walt Disney had a bad relationship with his father and changed the character of Mr Banks to be more distant Credit: Rex Features

Actress Karen told The Sun: “PL Travers’ father was nasty to her. Walt Disney had a horrible relationship with his father.” The mogul saw the story as a fantasy about children transforming a cruel father — like his own — into a loving one.

As a result, he changed the character of Mr Banks from the kindly one in the books to cold and distant.

And his painful memories of being an unhappy child — forced to get up at 4.30am to deliver newspapers in the snow — also made him determined to treat the child stars in Poppins well.

Karen recalled: “I learned the reason why Uncle Walt was so nice to me and my family is because he didn’t want another eight-year-old to have the s****y experiences he’d had.”

Disney treated the child stars in his movies well, because of his bad experiences growing up Credit: Kobal Collection – Shutterstock

Travers had seen the character of Mr Banks as a chance to bring back the bank manager dad she had idolised but who had died of alcoholism when she was seven.

She was appalled that he was now being made into a villain.

Born Helen Goff in the wilds of Queensland in 1899, Travers moved to England aged 25.

And despite creating the quintessentially proper character of Mary Poppins, her life was very unconventional by the standards of the day.

Travers hated the animated scenes in the Disney film Credit: Kobal Collection – Shutterstock

She enjoyed romantic relationships with both men and women.

For ten years she lived with Madge Burnand, the daughter of the editor of Punch — who once took a photo of Travers cavorting topless on an Italian beach.

Travers later fell in love with the poet Francis McNamara, an Irishman who once informed the author: “Mary Poppins, with her cool, green core of sex, has me enthralled for ever.”

Single again by the age of 40, Travers adopted a baby boy called Camillus from a large, struggling family in Ireland.

Dotrice (pictured with Van Dyke) continued acting until the age of 24 before retiring to become a mum Credit: Rex Features

What Camillus didn’t find out until he was 17 was that he had a twin brother, Anthony, who Travers had not wanted to care for despite his parents begging her to take them both.

On learning the truth he went off drinking with his sibling, a habit that was to develop into crippling alcoholism for both of them.

Camillus died in 2011 from the effects of his addiction.

The boys’ oldest brother, Joseph Hone, said: “I don’t think Travers was fit to bring up children.”

Julie Andrews won the Best Actress Oscar for her role Credit: Rex Features

She had reportedly chosen Camillus as the twin for her on the advice of her astrologer — and later became more and more obsessed by the stars, the occult and mysticism.

The popularity of Travers’ books faded over the years as racism in them became unacceptable — especially the shocking descriptions of black Americans.

In contrast, those involved in the film continue to thrive on their associations with the smash hit.

Julie Andrews, 83 — a stage star when she won the role — became a sensation, landing the Best Actress Oscar and her part in The Sound Of Music. She is now a dame.

Matthew Garber, who played Michael, died aged 21, after contracting hepatitis from eating bad meat Credit: �Walt Disney / Supplied by LMK

Karen says she and Matthew had a great time making the movie as children Credit: Walt Disney

Dick Van Dyke overcame his demons and became one of the most familiar faces on US telly.

Karen Dotrice continued acting until the age of 24, then decided: “I would rather just get married and become a mum and that was that.”

Tragically, Matthew Garber, who played her brother Michael, only made it to the age of 21.

Despite rumours that drugs played a part in contracting the hepatitis that killed him after a trip to India, his family insisted it was caused by eating bad meat.

He and Karen were a perfect team, working on other films together as children.

She said: “We had a great childhood. We made three films together.

“I wish he was here to give these comments too.”