A trio upset with a cook who had denied them free prata slashed him with a knife and left him with a deep wound.

Balachandran Kothandapani, 59, was yesterday sentenced to a year in jail, with the judge reminding him to act his age.

Before handing down the sentence, District Judge Mathew Joseph chided Balachandran, saying his conduct was "totally unconscionable" and that he was not "an immature 16-year-old".

He also said the cook - Mr Revi Jose Vibin, 33 - was entitled to refuse to give the trio free prata.

Balachandran had pleaded guilty on March 28 to being part of the group that assaulted the Indian national in July last year, and to possessing the knife used in the attack.

The court heard that Balachandran, together with Farizal Rahmat, 35, and Murugan Joseph, 45, frequented the prata stall at Block 710, Clementi West Street 2, where they often demanded free food. Court documents did not state if they received free meals prior to the attack.

On July 29 last year, the three men consumed alcohol at a nearby pavilion before heading to the prata stall at 5.13pm.

Murugan and Balachandran approached Mr Revi's colleague and ordered prata but they were not given any as they had no money. They then left the premises.

Murugan and Farizal returned to the stall at around 5.30pm and were turned down a second time.

The court heard that all three men returned about 10 minutes later and were enraged when Mr Revi intervened.

When he left the stall, the men followed him around the neighbourhood.

At some point, Balachandran left to retrieve a knife with a 19cm-long blade. When Mr Revi returned to the stall, the men attacked him.

Deputy Public Prosecutor Alexandria Shamini Joseph told the judge: "During the confrontation, the knife was passed around the group and the accused passed the knife to Murugan.

"Murugan, using the knife in his hand... then intentionally slashed the victim on the left side of his head."

The police were alerted and the cook was taken to the National University Hospital where he was treated for his wound. He was discharged the next day and given 14 days of medical leave.

Both Murugan and Farizal were dealt with earlier in court.

Offenders convicted of using a weapon to commit assault can be jailed for up to seven years and fined or caned. Balachandran cannot be caned as he is over 50 years old.