"The removal of potential legal delays to development imperatives is further exemplified by the issue of Constitutional rights to property. While Singapore was a state within the Federation of Malaysia, article 13 of the Malaysian Constitution guaranteed the right of property. On secession from the Federation, while other fundamental rights were adopted by the Republic of Singapore Independence Act, article 13 was conspicuously omitted from this adoption to preclude constitutional challenge and hence delay, by litigation on the adequacy of compensation for the compulsory acquisition of Land for public purposes."
--- State enterprise in Singapore: legal importation and development / Philip Nalliah Pillai
"Wee Chong Kin Commission (1966) recommended entrenching a provision to protect against torture & inhuman or degrading punishment or treatment - not accepted"
Another source says this was because of Death Penalty objections, yet another that in "Singapore's first self-conscious effort in constitution-making and institution-building... Parliament either rejected or ignored most of the Commission's recommendations"