interfere with its statutory duty". Despite initial resistance to recognition of this doctrine by the courts, the landmark GCHQ case firmly established procedural protection of legitimate expectations. In the case, strikes by civil servants at the Government Communications Headquarters had destabilized operations and were seen as a threat to national security. The Government of the United Kingdom took swift action to limit the rights of GCHQ employees to join unions, permitting them only to belong to an approved departmental staff association. The applicant organization challenged this decision by arguing that it should have been consulted because of a long-standing practice of doing so. In his judgment, Lord Fraser regarded the term legitimate as synonymous to "reasonable" and identified two ways in which a legitimate expectation could arise, namely, "either from an express promise given on behalf of a public authority or from the existence of a regular practice which the claimant can reasonably expect to continue." While the House of Lords ultimately held that the government action was not unlawful for reasons of national security, it agreed that there was a legitimate expectation on the facts due to the well-established practice of consultation between the government and the trade union on important matters affecting the latter. The court was of the opinion that if not for national security interests, the application to protect a procedural legitimate expectation through judicial review would have been granted. Protection of procedural legitimate expectations has since been firmly entrenched as one of the court's roles in judicial review. The importance of procedural fairness as enunciated in the GCHQ case is further illustrated by Re Police Association for Northern Ireland's Reference (1990). Applying the principles in the GCHQ case, the High Court of Justice in Northern Ireland held that the Police Association had neither been deprived of a legitimate expectation nor treated unfairly. The Court of Appeal of England and Wales also protected procedural interests by stating that a public authority cannot, without some form of warning, change a long-standing practice that it is aware an individual has acted in the light of and derived a benefit from, in the case of R v Inland Revenue Commissioners, ex parte Unilever plc (1996). Shift to protection of the substantive domain Although the courts' protection of procedural legitimate expectations assured individuals that decision-making processes were guided by fairness and thus the "greater propensity for fairer decisions", in some