The row erupted inside a unit of the Portland Building at around 11 pm yesterday, where the father allegedly used the mop to hit his son four times on his arms, fingers, and head.

Police’s initial investigation revealed that the beating came after a quarrel between the two, with the father dissatisfied with his son’s phone addiction.

The 15-year-old boy was taken to Kwong Wah Hospital for treatment, while the 49-year-old construction worker was arrested for 'Ill-treatment or neglect by those in charge of a child or young person.'

It is understood that the son lives with his parents and elder sister.