Housing and Development Board
The simple "ultra vires" doctrine was implicitly applied by the High Court of Singapore in "Wong Yip Pui v. Housing and Development Board" (1984), in which the Court had to determine if the Housing and Development Board (HDB) had the power to compulsorily acquire a flat which had been sold to the plaintiff under the Housing and Development Act. Section 48A(1)(b) of the Act stated: