Chief Justice Chan Sek Keong allowed the prosecution's appeal against the sentence meted out to Zhu Guo Feng, 25, in June.

Zhu admitted to kicking and scratching Corporal Hamzah Mohamed Aman with intent to deter him from discharging his duty at Boat Quay at about 2.30am last Nov 14.

He was also fined another $3,500 for disorderly behaviour and using abusive language, but the prosecution did not appeal against those fines.

Three other charges were taken into consideration.

The court heard that Cpl Hamzah and his colleague were patrolling along Boat Quay that night when they saw Zhu scuffling with a man and disturbing the public peace.

The officers warned them to stop several times but Zhu ignored them.

When Cpl Hamzah tried to restrain him, he kicked the victim several times on the right leg and scratched him.

Deputy Public Prosecutor Gillian Koh Tan argued that an attack on a public servant was a serious offence, and a custodial sentence was usually given.

The courts, she said, had generally imposed two to nine months' jail in cases involving assaults which were not serious.

But the district judge in this case had departed from the sentencing precedents, and given undue weight to Zhu's plea of guilt.

DPP Tan said Zhu showed little or no remorse and had actually punched another officer first before attacking Cpl Hamzah that night.

Zhu, who said he was very drunk then, could have been jailed for up to five years or fined or caned or received any two such punishments for the offence.