It was introduced in 1955 during the colonial era and intended to be a temporary measure, but has since been renewed continuously; the Government has declined to make it permanent, claiming it "believe[s] that the Act should be explicitly extended by Parliament every five years".

Between 2008 and 2012, the average number of detention orders issued each year was 43, and as of 31 October 2013 there were 209 people detained under the CLTPA; this had fallen to 109 in 2016.

It also renders illegal such actions taken in respect of other essential services unless 14 days' notice has been given, or during the course of proceedings taken to resolve trade disputes.

[8] In August 1958, the Ordinance was amended to provide for the preventive detention without trial of persons associated with criminal activities for up to six months.

Such fights were difficult for the police to detect and to prosecute, as eyewitnesses were too frightened of reprisals to furnish information leading to the arrests of gang members.

[10] He said: It is in these circumstances that the Government has decided that more drastic steps must be taken to protect the public from the activities of these gangs, and that since, for the reasons I have given, it is not possible to achieve that protection through the normal judicial processes of the Courts, these safeguards, which are adequate in ordinary times, must, in the present abnormal crime-wave, be supplemented by executive action.

It is not only the duty of the Government to do this in discharge of its primary responsibility for the maintenance of peace and good order, but I believe that there is a wide public demand that such action should be taken and that it will meet with wholehearted support from all law-abiding members of the community.

[14]After Singapore became a self-governing state within the British Empire, in September 1959 the Ordinance was amended again to extend the period of detention from six to 12 months, to give the Minister for Home Affairs the power to place persons associated with criminal activities under police supervision as an alternative to detention, and to impose special restrictions on persons under police supervision and special penalties on them for breaking the restrictions or being convicted of specified offences.

[24] It also contains section 1(2), a sunset provision which reads: "This Act shall continue in force for a period of 5 years" from a specified date, currently 21 October 2019.

[43] On 26 November 2012, 102 drivers from China employed by SMRT Buses refused to report to work, citing dissatisfaction with being paid less than their Malaysian and Singaporean counterparts and unhappiness with their living conditions.

Senior District Judge See Kee Oon imposed deterrent sentences on them "to ensure that others are not emboldened towards attempting similar displays of disaffection over employment terms or conditions".

He held that one aggravating factor was that the four drivers had planned the strike "ostensibly with the purpose of putting pressure on SMRT to accommodate their demands, but with the clear consciousness that it would cause disruption and inconvenience in the provision of transport services.

[49][50] Therefore, a court is entitled to determine whether there are objective grounds for the Minister's satisfaction that a person has been associated with criminal activities and that his or her detention is necessary.

On the other hand, it was held by the High Court in Re Wong Sin Yee that the judicial process is unsuitable for reaching decisions on questions of public safety, peace and good order.

While the Minister for Home Affairs must be satisfied that a detention order is required in the interests of public safety, peace and good order in Singapore, it does not follow that the threat to public safety, peace and good order must result from criminal activities in Singapore;[53] however, in the 2015 case of Tan Seet Eng v Attorney-General and another matter,[54] the Court of Appeal ruled the detention of alleged match-fixer Dan Tan unlawful as "there [was] nothing to suggest whether (or how) [his] activities could be thought to have a bearing on the public safety, peace and good order within Singapore", and thus "the Appellant's detention was unlawful because it was beyond the scope of the power vested in the Minister".

"[66] During a Parliamentary debate on the extension of the Act's validity on 13 February, the Senior Minister of State for Law and Home Affairs, Associate Professor Ho Peng Kee, said that since 1999 the number of detention orders issued under the Act each year, about 60 to 80, had remained "relatively low".

As of 31 October 2013, there were 209 people detained under the CLTPA, two-thirds for gang-related activity, a quarter for unlicensed moneylending, and the remainder for drug trafficking and other syndicated crimes.

However, Ong Yew Teck may no longer be good law in view of the Court of Appeal's more recent decision in Kamal Jit Singh (above).

[72] Such a police officer may, if satisfied that the enquiries cannot be completed within 48 hours, authorize the further detention of the person for an additional period not exceeding 14 days.

[78] A person thus arrested is deemed to be in lawful custody and may be detained for not more than 48 hours in any prison or police station pending the instructions by the Minister for his further detention.

[81] After a detention order has been made or after its expiry, the Minister may direct that the person be subject to police supervision for a period not exceeding three years.

[87] As the restrictions are absolute, a person need not possess any mens rea (fault element) to have committed an offence.

[93] A person subject to supervision who is convicted of an offence committed after the date of the supervision order under the provisions of any law specified in the Third Schedule to the Act is liable to be imprisoned for twice as long as the maximum term for which he would otherwise have been liable, and also to be caned, notwithstanding any other written law to the contrary.

[17] Part IV of the CLTPA contains various general provisions, including the following: Whenever the Minister for Home Affairs declares that an immediate threat to public peace exists within Singapore or any part of it, any police officer not below the rank of sergeant may command any assembly of 10 or more persons within Singapore to disperse.

[96] A police officer not below the rank of sergeant may, without warrant and with or without assistance, enter and search any premises, stop and search any vehicle or individual, whether in a public place or not, if he suspects that any evidence of the commission of an offence is likely to be found on the premises or individual or in the vehicle, and may seize any evidence so found.

[103] Notwithstanding anything to the contrary in any written law, a court may order that the whole or any part of any trial before it for any offence under the Act shall be dealt with in camera if it is satisfied that it is expedient in the interests of justice or of public safety or security to do so.

[113] A person who fails without reasonable excuse to submit to the taking of photographs and finger impressions, provide registrable particulars and other particulars, or submit to the taking of body samples[114] commits an offence and is liable on conviction to a fine not exceeding $1,000, imprisonment not exceeding one month, or both.

)[118] The Commissioner of Police is required to maintain a register of all photographs, finger impressions, registrable particulars; and a DNA database.

[120] Where an arrested person has been taken is released without having been convicted of any offence or placed on detention or supervision under the Act, all photographs, finger impressions, records of particulars or body samples taken from him must be removed from the register and DNA database.

Senior Minister of State for Home Affairs and Law, Associate Professor Ho Peng Kee, said: "This amendment will ensure that our DNA database is more comprehensive.