The 30-year-old father and the 31-year-old step-mother were sentenced in May 2021 to life imprisonment for murdering the little girl Z in early 2018; and nine-and-a-half years for abusing Z and the eight-year-old son X since 2016.

The 58-year-old step-grandmother was also jailed for five years for abusing the two children between August 2017 and January 2018.

The trio then filed an appeal against their convictions and sentences but was rejected by the High Court's Court of Appeal last year.

In the judgment released today, a panel of three judges including Andrew Macrae, Kevin Zervos and Maggie Poon Man-key wrote that: “This was a wicked and disturbing case, which will have shocked everyone in the community.

“As the [previous] judge remarked, it was ‘a case of extreme cruelty to the two children over a period of about five months.’

“Any parent who visits upon his or her own children (or step-children) the sort of physical and emotional cruelty and abuse described in this case, which has led to the death of one child and the severe and probably life-long emotional scarring of the other... deserves no mercy whatsoever.”

“The scale of abuse was graphic,” the judges also said, and noted this case demonstrated “the need for a substantial increase in the maximum sentences for this offense.”

The sentences were not a day too long, they added.