In May 2009, it was announced that Emmerdale's new series producer, Gavin Blyth, would introduce The Bartons, a new farming family, as part of an ongoing overhaul of the show.

[4] Of her casting, Powles said "I always wanted to act and especially because it's a northern show and my family live just down the road in Otley, so I've got a strong Yorkshire connection.

"[4] "When she arrived in Emmerdale Holly seemed just like any other teenage girl, but her growing dependence on drugs changed her personality dramatically and led her to lie and steal from her family.

Susan Griffin of the Liverpool Daily Post said she would not go short of an admirer or two, and Powles added "Holly wouldn't go for someone who was typically good-looking.

[13] A writer for the Sunday Mail said Aaron's offer leads "a disgusted Holly to storm out", leaving him feeling guilty.

[13] A Daily Record reporter stated that Aaron appeared to have destroyed any chance he had with Holly, but she showed "incredibly bad taste in the opposite sex" by choosing to date him.

What I didn't want to do was to run a three-week storyline which sees an addition, discovery and cure in such a short space of time - that's not what happens in real life.

[21] While out clubbing with Aaron Livesy and Jackson Walsh (Marc Silcock), Holly bumps into Roz and they drink and take cocaine.

[21] Powles said she has researched her character's storyline, by consulting a drug support group and talking to recovering addicts and the people who work with them.

[23] "I've learned through research that people from all walks of life become addicted – those who've had terrible childhoods and those, like Holly, who come from a good family.

[24] Ashley and Douglas Potts (Duncan Preston) find Holly in the graveyard and they call John and Moira to collect her.

[27] Powles told a writer for All About Soap that Holly lost her friends and her independence when she became addicted to drugs and John protected her.

"[27] Holly begins to resent Moira when she sees her lying around grieving for John because she blames her for causing a split within the family due to her affair with Cain Dingle (Jeff Hordley).

[27] Powles said "The agony's overwhelming and the only thing Holly can think of to get over the pain is to take a hit of heroin, so she succumbs - and goes out and scores a couple of wraps.

Powles added that Holly does not want to cause her family anymore heartache, but she will carry "the heroin-taking ghost" in the back of her mind forever.

[28] She is still not ready to let go and Powles told Inside Soap's Katy Moon "John's funeral was bad enough because she was trying to be strong for her brother and sister.

[28] Moon stated that Holly takes Alex's words the wrong way and she feels that the only way to get through the situation is to numb the pain with heroin.

[28] Powles stated "The Bartons find it very difficult to swallow their pride and accept that Cain deserves their thanks, but Holly is really defensive of him.

[29] Powles later told Claire Donnelly of The People that she was starting to feel "a bit tied down" with her routine and she got itchy feet.

[32] On 5 February 2016, new series producer Iain MacLeod announced that Powles had reprised her role and would be returning to Emmerdale the following month.

[35] In an interview with Daniel Kilkelly of Digital Spy, Powles told him that when she was asked to return, she had known it would only be for a six-month storyline focusing on Holly's drug addiction.

[36] Powles found the storyline "challenging", but pointed out that it was "a very serious and stark warning" showing the effects that drug addiction can have on people.

Holly steals Scarlett Nicholls' purse to get money for drugs and babysits Viv Hope's (Deena Payne) children while high.

Holly, Hannah and Adam are delighted when John and Moira announce they are back together and they book them a hotel room for a night.

Moira falls on a used needle whilst going to confront Simon, Holly's drug dealer and believes she has contracted HIV.

Holly finds support from fellow drug addict Jai Sharma (Chris Bisson) and they date in secret.

[38] He added "With a powerful and moving performance by relative newcomer Sophie Powles, Holly Barton has been transformed from a vivacious young student to a drug-ravaged, emaciated heroin addict over the last few months.

"[39] Simon later asked "If one of the Bartons had to die, why couldn't it have been vile Holly with her stupid voice like a creaky door?

"[40] Claire Donnelly of The People said Powles had made "quite an impact as junkie Holly", with some members of the public coming up to the actress and asking her for drugs in the street.

[41] The nomination made the viewer-voted shortlist,[42] but it lost out to the return of Andy Carver (Oliver Farnworth) in Coronation Street.