Southern Thompson subjected her toddler Comfort to prolonged neglect and abuse, leaving the little girl malnourished, confined to her cot and covered with injuries including black eyes, a cut lip, and bruising to almost every part of her tiny body.

Her final act was inflicting blunt force trauma on the 18-month-old, causing her a fatal brain injury in their Tīrau home in July 2018.

But Southern denied the murder then cut off her electronic monitoring bracelet and went on the run days before she was to stand trial, only to plead guilty a month before her second trial date, four years on from the death of her daughter Comfort Thompson-Pene.

Now, Southern, who was jailed for life with a minimum period of imprisonment of 17 years, has argued the MPI was manifestly unjust considering she was remorseful and had a difficult upbringing.

In the recent challenge, her lawyer Susan Gray told the Court of Appeal that those factors warranted around three years being shaved from Southern’s MPI.

But Justices Sarah Katz, Matthew Palmer and Pheroze Jagose, who heard the appeal, disagreed.

In last week’s decision, given by Justice Katz, it said there was no disputing that Southern came from a very disadvantaged background and that there was some causal nexus between this and her offending.

“In the overall circumstances of this case, however, Thompson’s personal circumstances are not sufficient to displace the mandatory minimum period of 17 years’ imprisonment.”

According to the decision, Southern was sentenced on charges of murder, ill-treatment of a child, injuring her with intent and failing to seek medical care.

The charges other than that of murder came following a series of events that occurred from at least January 2018 until Comfort’s death on July 24 of that same year.

During that period, Southern regularly mistreated and physically abused her daughter in numerous different ways, including slapping and hitting her, grabbing her with excessive force and scratching her.

She failed to change her dirty nappies and to keep her clean and warm. She also did not feed her properly and kept her confined to her cot and a couch for extended periods, punishing Comfort if she tried to leave those areas.

At one stage the toddler had two black eyes, a torn frenulum - the thin membrane of skin in the centre of the top of the mouth, and a fractured clavicle.

Southern Thompson challenged her sentence in the Court of Appeal. Photo: NZME.

Following her death, a post-mortem examination revealed soft tissue bruising to almost every part of her body and extensive scratch marks.

Comfort weighed just eight kilograms and was plainly malnourished, the decision stated.

It detailed that on the day before her death, Southern called Healthline for advice, stating her daughter was unwell. Based on what she told them, she was told to phone 111 as Comfort needed urgent medical care. But it was not for another two hours that she made the call.

Comfort died in hospital the following day and Southern was charged with her murder soon after.

At sentencing, the judge took a starting point of 18 years and six months imprisonment when setting the MPI. A reduction was made for Southern’s belated guilty plea and discounts were given for personal circumstances and her remorse, bringing the MPI to 16 years and three months.

But the judge then found the case triggered Section 104 of the Sentencing Act, which called for a non-parole period of at least 17 years to be imposed.

In her appeal, Susan argued that such an MPI was manifestly unjust and that the discounts were insufficient.

She submitted that had Southern’s circumstances and remorse been adequately recognised, an appropriate MPI would have been around 14 years.

Reports provided to the sentencing judge detailed an upbringing marred by a dysfunctional family environment, poverty and deprivation. Southern witnessed physical violence in her home and was abused herself. She began using alcohol and drugs at a young age and her mental health suffered.

The alcohol and drug use continued into her adult years, and the judge says her living arrangements in the months leading up to the death of Comfort were particularly abysmal. She lived with several other family members and their children in circumstances described as squalor, and nobody was prepared to take responsibility for looking after the children.

Susan submitted Southern’s deprived background was part of her narrative and formed part of the background to the offending.

She says it was apparent Southern was ill‑equipped to deal with the stresses of life - a life characterised by instability and dysfunction.

The Crown opposed the appeal, submitting the discounts were appropriate.

Though it was accepted there was a link between Southern’s background and her offending, the Crown challenged the extent.

“Ms Thompson’s other two children appear to have been well cared for and showed no signs of injury or neglect when examined at the time of Comfort’s death. Despite her deprived background, Ms Thompson was therefore able to exercise self-control and choice in her treatment of her other two children.”

The Court of Appeal justices rejected the appeal, finding the sentencing judge had not erred in his ruling.

“Of course child homicides often occur in complex relational and domestic situations. They bear upon the offender frequently to evoke sympathy and mitigate the offending. They are to be taken into account for sentencing.

“But they should not cloud the essential fact that the violent, cruel and brutal treatment of a defenceless and vulnerable child, to whom there are duties of trust and responsibility, constitutes conduct of grave criminality and, where death ensues, the sentencing task is in respect of a very serious crime.”