Two teenagers who were jailed for the gang rape of a 14-year-old schoolgirl had their convictions overturned yesterday on a legal technicality. The Court of Appeal reversed the convictions of Cheng Sai-wai, 17, and Tam Pak-kin, 15. The pair had each been sentenced to 7.5 years over the vicious gang sex attack on the girl in a Tsing Yi park in June 1996. They had denied raping her. Mr Justice Pang Kin-kee, who sentenced the teenagers on May 9 last year, let the jury decide whether verbal confessions had been forced from the teenagers by the police. Until a Privy Council ruling a month later, this was the accepted practice by Hong Kong courts. In an oral confession made to police immediately after the attack, Cheng said: 'I mounted the girl, but it was others who mounted her first. Only when they had finished, they told us to mount her,' the Court of Appeal heard. The Privy Council ruling from London in June last year said Hong Kong judges were supposed to decide in a pre-trial hearing if oral statements were voluntary. Cases made before the June ruling have since been challenged. Last week, in a separate appeal for the same attack, the court reduced the sentence of the gang's leader, Kong Ka-chun, 17, who had admitted raping the young girl twice. Because of the same legal technicality, his eight-year sentence was reduced to 6.5 years. 'It was quite clear from the short reasons given by Mr Justice Pang when he ruled all the statements to be inadmissible that he had not ruled on the oral admissions,' Mr Justice Simon Mayo said yesterday. During the appeal the prosecution 'accepted the judge had been in error in not so ruling', Mr Justice Mayo said. On June 9, 1996, the schoolgirl was taken to Mayfair Park, Tsing Yi, by a gang of teenagers where she was 'manhandled and indecently assaulted . . . Kong slapped and punched her,' the Court of Appeal heard. The attack 'escalated further when the group decided that some or all of them would have sexual intercourse with her', the judges said. 'The girl resisted this as best she could and asked the youths to stop. The men had sexual intercourse with her successively.' Mr Justice Mayo was sitting with Mr Justice Noel Power and Mr Justice Michael Stuart-Moore. Although Cheng and Tam had their rape convictions quashed, the Court of Appeal said that on Monday it would hear arguments from the prosecution for a retrial.