Coronation Street star Claire Sweeney has explained her character Cassie

Plummer’s shock poisoning story.

Earlier this year, Cassie began caring for Ken Barlow following his fall, with the

pair forming a close friendship.

Ken confided in Cassie about his £50,000 premium bond win, which he decided to spend on a holiday for them both.

In Monday’s (November 18) episode, Ken returned from holiday and told his family that he couldn’t afford to keep Cassie on, with his relatives secretly relieved that she’d be out of the picture.

Cassie seemed to take the news well as she began searching for other jobs in the area, but was later seen spiking Ken’s tea with crushed tablets.

Spoilers for Wednesday’s (November 20) episode have revealed that Ken will be rushed to hospital, before offering to pay Cassie an extra pound per hour to keep her job after all.

Speaking about the storyline, Sweeney revealed she was “shocked” to learn that her character would poison Ken, as he’s a “national treasure”.

“I’m going to be public enemy number one! I think viewers are going to hate her,” she added. “The funny thing is that they’ve just started to like her – they were finally warming to her – and then this happens.

“In my head, playing her, I’m trying to find saving graces, but I don’t know if there will be any. I’m a Corrie fan and I’d be fuming watching this.”

Sweeney went on to explain that Cassie doesn’t intend to hurt Ken. Instead, she wants him to “need” her because she doesn’t want to lose the close bond they’ve formed.

“When Ken says he can’t afford to keep her on, she’s devastated,” she said. “There’s an anger and a hurt and a feeling of abandonment. It’s not even necessarily money-orientated, she likes the life she’s got looking after him. There’s an element of Munchausen’s to it.”

The actor also spoke about Cassie’s “remorse” after Ken is taken to hospital, before sharing how the character will continue her plan to keep Ken under her influence.

“She Googles drugs that make you drowsy and comes across antihistamines,” she revealed.

“I think Cassie will go to any lengths to keep this going. She’s not poisoning him with the intention to harm him, it’s just to keep him a little bit dopey, so he keeps her on, so he needs her.

“Everything she has done with survival in mind. She was on the game; she was abused when she was younger – so everything is about survival and I think this is about survival as well.”

On whether the storyline could signal the end of her time on the cobbles, Sweeney admitted that it had crossed her mind, but she is “grateful” for the experiences she’s had.

“When I got this job, if you’d have told me that a year and a half later, I’d be here having a big storyline with Bill Roache [who plays Ken], I’d have been so grateful for that,” she said. “If this does signal the end, I’d go, ‘Well, hasn’t that been great? I’ve been blessed.'”