After a court hearing to hand down sentences to 22 Wo Hop To members on May 3, Judge Line invited the undercover Police Constable, nicknamed 'Andy', into the court and commended him for his bravery.

The triad society members were jailed for up to seven years each as a result of the evidence given by Andy who had infiltrated the gang.

Judge Line presented Andy with a commendation letter and asked the Director of Public Prosecutions to pass a copy of it to the Commissioner of Police.

The letter said Andy was a witness of the highest quality.

"I can also appreciate those qualities of his character that made him volunteer for the assignment. He was of a junior rank and had no special training of any real significance, but that mattered not as it was intelligence and firmness of character that made his job a success.

"It was a success as it has resulted in the conviction and punishment of a section of Wo Hop To that was committed to the use of violence. It has put behind bars men who deserve to be there," Judge Line said.

He added Andy undertook a job that exposed him to danger, mixing with the vicious characters, and there was good reason to fear the consequences if they had discovered his true identity.

"In doing his job he was for much of the time alone and beyond the help of his fellow officers. The people he mixed with and the values he was forced to adopt must have been repugnant to him.

"There was a real element of personal sacrifice on his part for which we must all be indebted to him," Judge Line said.

He pointed out that there could be no doubt triad societies posed a menace to Hong Kong.

"In the continual fight that the Police wage against them the role of the undercover officer remains one of the greatest importance.

"And we must never forget the sacrifices and risks such brave men undertake on our behalf," he added.

Wo Hop To is an active triad society in the Hong Kong Island Region.

In October 1997, in order to interdict the illegal activities of Wo Hop To members, the senior management of Hong Kong Island Region decided to mount an undercover operation by using a police officer as an agent to infiltrate the triad group. The operation was supported by the Department of Justice.

Andy volunteered to become an undercover agent and was selected to take up this important task.

The operation started in November that year.

Chief Inspector of the Hong Kong Island Regional Anti-Triad Unit Tommy Yu said: "Through his professional effort and dedication, Andy managed to mix with a Wo Hop To triad faction in January 98."

"In June 1998, action was taken against the triad group.

"A total of 48 persons including office bearers of Wo Hop To were arrested by various units of the Hong Kong Island Regional Headquarters," Mr Yu said.

Thirty-two people were charged with a total of 154 offences.

The main trial against 23 of them was concluded on May 3.

The defendants, aged 15 to 46, were found guilty of multiple charges.

They included assisting in the management of a triad society, claiming to be triad society members, inviting others to join the group, unlawful assembly and wounding.

They occurred between January and June last year.

Except for one, whose sentence had not yet been passed, Judge Line meted out enhanced sentences under Section 27 of the Organised and Serious Crimes Ordinance on eight of the 22 defendants.

One of them was sentenced to seven years, which is the maximum term that can be imposed in the District Court.