Estoppel (principles?) in public law : the substantive protection of legitimate expectations

• Main Author: Knight, Dean R.
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/15270

This thesis examines the doctrine of public law estoppel and similar doctrines, such as substantive legitimate expectation, which seek to give substantive protection to people's expectations arising from their dealings with public bodies and officials. The substantive protection of expectations in public law is controversial and this thesis considers whether the concerns raised about its application have any sound basis. I review the case-law in which the courts have considered whether to apply estoppel in public law or otherwise extend the doctrine of legitimate expectation to substantive outcomes. Particular attention is paid to the "spill-over" of estoppel from private law into public law. I discuss whether there is any real difference between the doctrines which seek to give substantive protection to expectations. I conclude there is no material difference between the approaches or their inherent ability to respond to the concerns raised by the opponents of substantive protection. I then consider the notion of legal certainty in the law - the conceptual principle on which the doctrines of estoppel and legitimate expectation are based. I conclude that this principle has a strong foundation and creates a powerful argument for protecting expectations. I then examine the apparent concerns that arise from achieving legal certainty in public law and draw out the specific objections to applying public law estoppel and substantive legitimate expectation. I critique each of these objections and conclude that none of them present an insurmountable hurdle to the application of estoppel or substantive legitimate expectation in public law. I conclude by setting out a number of "touchstones" to assist in the case-by-case assessment of whether expectations should be protected. The touchstones attempt to place a greater emphasis on the underlying theoretical justification for protecting expectations and to ensure the assessment deals with the concerns that were raised about bringing the concept of legal certainty into public law.