A HEADMASTER told a court yesterday that a former student had made more than 20 nuisance telephone calls to him per day over a four-day period. Mr Fung Ying-luen, headmaster of the Chang Ming Thien College of the Tung Wah Group of Hospitals in Shekkipmei, was testifying in the trial of student Wo Hang, 21. Wo, a student of the college six years ago, is charged with making persistent telephone calls without reasonable cause and for the purpose of causing inconvenience to Mr Fung. The defendant, who is not legally represented, denied having persistently made calls to Mr Fung's direct line in the principal's office of the college between September 22 and 25, last year. He was warned by magistrate Mr Kevin Ball when he was seen laughing during Mr Fung's testimony. Questioned by prosecutor Mr Dominic Smyth, Mr Fung said he had reported to police that nuisance calls had been made to three telephones at the college including his office phone. He said the caller, whom he recognised as the defendant, uttered abusive language to him when the calls started on September 2. He remembered that Wo had gone to his office on August 27 and later made a scene outside the college. Asked about the purpose of his visit, Mr Fung said Wo told him that teachers and workers at the school had been unfair to him. ''He said that he wished to study in the United Kingdom, but he had no money,'' Mr Fung said. ''He requested the school to pay him compensation and said if the school failed to do so, he was going to do some harm to the school.'' He said Wo again made a scene outside the college and posted papers which contained words abusive to teachers of the college. Cross-examined by Wo, Mr Fung said most of the calls contained foul language. The court heard the incoming nuisance calls were later traced by the Hongkong Telephone Company, with the help of Mr Fung. Earlier, Wo alleged that there were alterations in a copy of the cautioned statement which he made to police on October 30 last year, adding that somebody was allegedly perverting the course of public justice. The hearing continues today.