Shianne Treanor was parted from her mum at the age of nine (Pic: NC)

Shianne Treanor spent a happy childhood with Dennehy, who read stories from romantic novels and did art projects with her.

She said the 36-year-old was "just a really big kid", and they would splash about in the paddling pool and make mud pies.

But Dennehy's life was secretly spiralling out of control. She got hooked on booze and drugs and had casual sex with men and women.

Aged nine, Shianne was parted from her mum when her father John Treanor, 42, left Dennehy and took their kids with him after she threatened him with a knife.

And the youngster's world fell apart four years later when her dad called during a sleepover at a pal's house to tell her: "Your mum has killed someone."

In fact, Dennehy had stabbed three men, torturing one. She dumped their bodies in ditches near Peterborough, Cambs, over a 10-day period in 2013.

At her trial the following year the psychopath admitted three murders and two attempted murders.

She is one of only three women to be given a whole life-jail term. The other two are Rose West and the Moors murderer Myra Hindley.

Sadomasochist Dennehy admitted to a psychiatrist that she killed for fun, adding: "It got moreish and I got a taste for it". Now 19 and speaking for the first time about the case, Shianne said: "She deserves to spend the rest of her life in prison.

Shianne described Joanna as "just a really big kid" (Pic: NC)

"I'm sorry for the victims - I can't imagine what they went through."

The teenager said that for years she was told nothing about her mother, and wanted answers.

She finally got them when she turned 18 and decided to look into the case. She said: "Eventually, I got an email telling me where she was.

"In October last year I wrote her a letter. I was really cold because I thought she hated me. I told her I wasn't looking for a relationship but I wanted to know why.

"But I got a letter full of love and warmth and how much she wanted to have me in her life. I just cried, it was so emotional."

Dennehy was arrested for stabbing three men and dumping their bodies in a ditch (Pic: NC)

Shianne visited Dennehy at HMP Bronzefield, Surrey, late last year.

Reliving their meeting she said: "I was nervous, shaking. When I got into the visit hall I had to take a double look when I saw her.

"She looks completely different. She's got short blonde hair and piercings on her face, one next to her eye. She looks well. I said, 'I've missed you'. In all honesty, I never thought I'd see her again.

"I never thought she'd do what she did or that she'd ever be in my life again. We both just cried."

Shianne went on: "I asked her, 'Why?'. She's apologised to me.

"It doesn't make it right and doesn't excuse anything, but I wanted the apology.

"Part of the punishment is that she will never get to see me grow up or get married." The teenager remembers Dennehy as a typical parent before drink and drugs took over.

"My mum would love to read," she said.

"She was always on the sofa reading a book and she would go out on long walks. She loved Mr Darcy, she read Pride And Prejudice. She would talk to me about it all the time.

"She'd do papier-mâché art with me and my friends. I had another friend and in the summer mum would get the paddling pool out and we'd do somersaults into it and make mud pies. She was just a really big kid."

Shianne and her sister have lived with their dad ever since their parents separated (Pic: NC)

When her parents split up, Shianne and her sister moved with their dad to Glossop, Derbys.

Shianne now lives in Manchester and recently completed a course in travel and tourism at a local college.

For years she worried she would inherit evil Dennehy's psychopathic tendencies. But she vowed: "I will never turn out like my mum. I'm my own person. She gave birth to me and I might have some personality traits of hers, but we're two different people.

"I was not around her for many years." Shianne added: "I can't believe she did what she did. It makes me want to cry. She's hurt those people and I can't ever forgive her for that.

"She should spend the rest of her life in jail thinking about the misery she's caused."