Lord Fraser of Tullybelton in ATTORNEY-GENERAL OF HONG KONG V. NG YUEN SHIU (1983) 2 A.C. 629 said that, “When a public authority has promised to follow a certain procedure, it is in the interest of good administration that it should act fairly and should implement its promise, so long as implementation does not interfere with its statutory duty”.
RATIONALE BEHIND LEGITIMATE EXPECTATION
Para. 62: “The rationale behind the doctrine of legitimate expectation is the need to prevent administrative authorities from exercising their discretionary powers so as to defeat legitimate expectations of individuals, which have been engineered by the prior conduct of those administrative authorities. Thus, the doctrine strives to make sure that administrative authorities are bound by their undertaking. In the case of ČAKAREVIĆ V. CROATIA (Application no. 48921/13) 26 April 2018, the ECHR Court held that, as a rule, a legitimate expectation of being able to continue having peaceful enjoyment of a possession must have a ‘sufficient basis in national law’.”
— Boley v Liberia & Ors. (2019) – ECW/CCJ/JUD/24/19