SINGAPORE - A company managing director was sentenced to a year's jail on Thursday (Sept 7) for assaulting his then 10-year-old son, causing a fracture to the boy's right eye socket.

The man, who is now 51 years old, originally claimed trial to the offence.

But on the first day of the trial on Aug 10, he decided to plead guilty to causing grievous hurt to his son.

An assault charge involving the boy's 41-year-old mother was taken into consideration during sentencing.

The man, who cannot be named due to a gag order to protect his son's identity, committed the offences in their house in the Yio Chu Kang area at around 10.15pm on May 28, 2015.

He was undergoing divorce proceedings with the boy's mother at that time.

The marriage soured several years earlier, and the couple slept in separate rooms.

The boy shared an upstairs bedroom with his mother while his father slept downstairs.

The man came home that afternoon and scolded his son over his unsatisfactory grades at school.

After downing some drinks at around 10.15pm, he went to the boy's bedroom and had a discussion with his wife about their son.

When the boy overheard them, he said: "You like that woman more than us. Why do you care for us so much?"

The man's lawyer, Mr Ravinderpal Singh, told District Judge Hamidah Ibrahim that the boy had taunted his father about a "China mistress". However, court papers did not reveal if she really existed.

The court heard that the boy repeated his remark after his father exclaimed: "What (did) you say?"

Furious, the man approached his son and kicked his face and body. He also pulled the youngster's hair and arms.

Deputy Public Prosecutor Kong Kuek Foo said: "(The boy) was lying on the floor and tried to defend himself with both hands. (His mother) immediately tried to intervene and tried to shield her son with her body, during which she was kicked (in) the back by the accused."

The man then pushed her, and she fell backwards, hitting her back against a vase and a safe.

He continued to punch his son's face when he heard the boy uttering an expletive.

The family's domestic helper, who witnessed the ruckus, alerted the police. Officers arrested the man when they arrived at the scene.

The boy was taken to KK Women's and Children's Hospital, where he was found to be suffering from injuries that included a fractured eye socket and a bruised forehead.

DPP Kong, who urged Judge Hamidah to jail the man for 15 months, said he had assaulted a vulnerable victim.

Mr Singh, however, asked for the lowest possible sentence and said that his client had "snapped".

He added that according to the man's sister, the boy is "generally a disrespectful young boy involved in unhealthy habits such as lying and stealing".

The man is now out on $20,000 bail as he might appeal against his sentence.

For causing grievous hurt, he could have been jailed for up to 10 years and fined. He cannot be caned as he is above 50 years old.