IN ONE of the largest security operations mounted in Hong Kong for the transfer of a prisoner, the last suspected drug baron awaiting extradition to the United States was flown out of the territory under heavy police guard. Police had feared an armed attempt by a mainland gang to free Chui Kin-wing before he flew out on Friday afternoon. The 41-year-old prisoner, believed to be a key figure in major drug syndicates, was allegedly involved in smuggling more than $2 billion worth of heroin into the US. Wearing leg irons, handcuffs and a waist chain, and guarded by Narcotics Bureau and Emergency Unit officers in bullet-proof vests, Chui was driven through Kowloon from the Lai Chi Kok Reception Centre just after 7 am, to Kai Tak. Traffic officers closed all roads that were part of - or crossed - the planned route, even allowing the police convoy to drive the wrong way down one-way streets. The group was met at Kai Tak by the armed Airport Security Unit and taken straight to a holding area at the airport. Chui was held there for about six hours before he was escorted to a plane flying to Los Angeles and handed over to US marshals. He was later transferred to another flight for New York. According to one officer, Chui wept when he realised he was going to be extradited, and said a gang was meant to free him during the move to Kai Tak. No incident took place during the journey to the airport. Chui is due to appear in a New York court this week to face heroin smuggling charges. Chui, who allegedly attempted to shoot a detective when he was arrested last year after a four-year investigation, became the second alleged heroin dealer to go to New York voluntarily in less than three weeks. On October 30, Cho Shu-wah was extradited to the US after unsuccessfully making two habeas corpus applications and while in the process of appealing to the Privy Council. Both men were believed to be behind the shipping of hundreds of kilograms of heroin to the US, with a street level value of more than $3 billion. Chui was arrested in September last year, when police simultaneously raided 16 premises in Hong Kong and arrested six people wanted by US authorities. Two other suspects were picked up later. According to one officer, Chui ''violently resisted arrest with a fully loaded five-round .38 Special Smith and Wesson revolver''. Ten rounds of ammunition and a number of holsters and handcuffs were found in his North Point flat, and the police Financial Investigation Group restrained more than $10 million worth of assets which it traced to the syndicate. An international investigation into the syndicate started in 1988 after 18 kilograms of No 4 heroin destined for the US, and four pistols were seized in Sheung Shui. Profits from the drug smuggling, which detectives believed involved at least eight consignments of top grade heroin totalling more than 515 kg shipped to the US between January 1987 and June 1989, were laundered back to Hong Kong. One member of the gang, Li Ah-kong, was murdered in April 1991 at the ''behest of one of the other syndicate members'' when he failed to deliver the proceeds from a 14 kg heroin consignment.