Council of Civil Service Unions and Ors. v. Minister for the Civil Service (1984)3 All E.R. 935 where it was held, inter alia, that an aggrieved person was entitled to invoke judicial review, if he showed that a decision of a public authority affected, him by depriving him of some benefits or advantage which in the past he had been permitted to enjoy and which he legitimately expected to be permitted to continue to enjoy, either until he was given reasons for its withdrawal and the opportunity to comment on those reasons, or because he had received an assurance that it would not be withdrawn before he had been given the opportunity of making representations against the withdrawal. It was further held that the appellant’s legitimate expectation arising from the existence of a regular practice of consultation which the appellant could reasonably expect to continue, gave rise to an implied limitation on the Minister’s exercise of the power contained in Art. 4 of the Civil Service Order in Council, 1982 namely, an obligation to act fairly by consulting the civil service staff before withdrawing the benefit of trade union membership.
DOCTRINE OF LEGITIMATE EXPECTATION IS BASED ON REGULAR PRACTICE
“The doctrine of legitimate expectation is not in the realm of estoppel. The court below thought it is a specie of estoppel. lt slipped. The cross-appellant is right to submit that the doctrine is not an estoppel. What the doctrine postulates is that where a public body or person acting in public authority has issued a promise or has been acting in a given way the members of the public who are to be affected by the scheme of conducting public affairs in the charted manner would, by law, require the promise or practice to be honoured or kept by the public body or person acting in public authority, save where there exists sound basis not to so insist on the settled scheme of conducting public affairs. The doctrine, therefore, enjoins public bodies to be fair, straight-forward and consistent in their dealings with the public. In other words, the doctrine of legitimate expectation is based on the existence of regular practice by a public body which the claimant can reasonably expect to continue or subsist and thus relies on the state of affairs to conduct or arrange his business or affairs in anticipation of the availability of the regular practice to cater for the case of the claimant. Fair and open dealing are the pillars of the doctrine. And fairness requires that the exercise of the doctrine of legitimate expectation be moored to full disclosure or utmost food faith by the potential beneficiary of the doctrine.”
– FBIR v. HALLIBURTON (WA) LTD (2014)