drug activity more aggressively through legal means, vice operations, and the establishment of an Opium Treatment Centre on St John's. They revised the Dangerous Drugs Ordinance of 1951 in 1953 to increase their authority to prosecute opium-related crimes, and initiated vice operations, such as the major opium crackdown of 1952. The Opium Treatment Centre was established under an amendment to the Dangerous Drugs Ordinance in 1954, marking the colonial government's first attempt to rehabilitate addicts. Formerly, addicts were simply imprisoned. Institutions have previously attempted to rehabilitate addicts, but only a fraction of patients were permanently cured. The centre opened in February 1955 and was managed by the Prisons Department. The opium treatment programme had three phases: withdrawal, rehabilitation and follow-up. Gradual withdrawal from opium typically lasted two to four weeks in the prison hospital. The subsequent rehabilitation phase would last six months to a year at the Opium Treatment Centre on St John's Island, during which patients were taught new skills such as carpentry to aid future reintegration into society. The experimental opium rehabilitation programme was noteworthy for medical institutions and was later claimed to cure the majority of those admitted; however, its criteria of admittance were controversial. During the centre’s opening, the Commissioner of Prisons Major Sochon claimed that the United Nations Organisation had taken note. It was also claimed by the Singapore Free Press that only six of about 400 addicts treated within two years of its opening had relapsed. By 1966, more than 4,000 opium addicts had been rehabilitated at the centre. However, the apparent success of the centre must be prefaced by their denial of treatment to long-time addicts whom they evaluated to be incurable. By the 1970s, opium addiction had greatly declined, although the extent to which this success can be attributed to the treatment centre is unknown. Despite the decline in opium addiction specifically, the number of arrests due to drug offences, in general, had increased between 1971 and 1973. In response to the increasing number of drug offenses in Singapore, in 1973, the government converted the Opium Treatment Centre to a Drug Rehabilitation Centre for treating all types of drug addicts, especially young adults. This rehabilitation centre was shut down in 1975 as the island was to be redeveloped by the Sentosa Development Corporation into a resort centre. Temporary settlement for refugees St John's Island was also a temporary settlement for refugees in