|This article does not cite any references or sources. (December 2009)|
In English law, the concept of legitimate expectation arises from administrative law, a branch of public law. In proceedings for judicial review, it applies the principles of fairness and reasonableness to the situation where a person has an expectation or interest in a public body retaining a long-standing practice or keeping a promise.
The traditional constraint on a public body has been the test of irrationality, also known as Wednesbury unreasonableness following Associated Provincial Picture Houses Ltd v. Wednesbury Corp which stated that a decision would be unreasonable if, ". . .no reasonable authority could ever have come to it" (per Lord Greene). But if the courts are to establish a justification for a more interventionist approach, irrationality will always be defeated if the particular decision has sufficient qualities of reasonableness, i.e. it should never be irrational to prefer the good of the many to the interests of the few. Hence, when faced with claims of a legitimate expectation, the courts have begun to require public officials to adopt the same approach as in making decisions affecting fundamental human rights (now formally protected through the Human Rights Act 1998 which incorporated the European doctrine of legitimate expectation to protect the public interest in consistency and certainty through a test of proportionality).
In procedural terms, a person is entitled to a fair hearing before a decision is taken if he or she has a legitimate expectation of being heard. But the fact that a person is entitled to make representations does not, of itself, constrain public bodies which, subject to a duty not to abuse their power, are entitled to change their policies to reflect changed circumstances even though this may involve reneging on previous undertakings. If there is a substantive limitation on this right to make changes, it lies in a test of fairness where the public bodies are equivalent to a breach of contract or there have been representations that might have supported an estoppel and so caused legitimate expectations to arise. It is, of course, difficult to prove such a legitimate expectation unless fairly specific representations as to policies affecting future conduct have been made. The form of generalised understandings that ordinary citizens might have will not be sufficient for this purpose. And, even if there are legitimate expectations, there is no absolute right to have those expectations met. Fairness may require no more than a hearing or consultation before any change is finally decided and, if the citizen's expectation is real, the courts might require the public body to identify an overriding public interest to trump the particular expectation.
This supplements the Wednesbury approach but it may not be advancing judicial review very far since, even in cases where an estoppel might otherwise have arisen, it will be difficult to convince a court that going back on a specific representation relied on to produce detriment will be unreasonable, unfair or irrational.
The idea of legitimate expectation has received sufficient mention both academically and in case law to effectively merit reference as a doctrine. Legitimate expectation can be classified as a new category of fairness, with Bingham MR in R v Inland Revenue Commissioners Ex Parte Unilever Plc  stating '...the categories of unfairness are not closed, and precedent should act as a guide not a cage'.
The principle idea behind this doctrine is that once a public authority makes a promise, it effectively amounts to a contract and going back upon it is a breach of contract and unfair for a public authority to do so, with legitimate expectation thus being the public law equivalent to the doctrine of estoppel. The case of R v North and East Devon Health Authority, Ex parte Coughlan (2000) showed that legitimate expectation is recognized in cases where the relevant authority had made an unequivocal promise to provide the disabled woman with a home for life on which she subsequently relied on that promise and sold her house. The court specifically made reference to the parallel with contract and the doctrine of estoppel. The clearest mention of the doctrine of legitimate expectation came from Laws LJ in the case of R (Nadarajah) v Secretary of State for the Home Department (2005) when he stated that 'the principle of good administration required public authorities to be held to their promises would be undermined if the law did not insist that any failure of refusal to comply is effectively justified as a proportionate measure in the circumstances' with proportionality depending on the interests being balanced on each case. However, while analogous to the law of estoppel, there are differences with it as well. Lod Hoffmann pointed out in the Reprotech case (2002) '...remedies against public authorities also have to take into account the interests of the general public which the authority exists to promote'.
Reference to legitimate expectation is also made in the early and famous GCHQ case by Lord Frasier who briefly sums up the courts decision in O'Reilly v Mackman in regard to legitimate expectation as being 'Legitimate or reasonable expectation may arise either from an express promise given on behalf of a public authority or the existence of a regular practice which the claimant can reasonably expect to continue'