In Middletown Policemen's Benevolent Ass'n Local 124 v. Township of Middletown, 162 N.J. 361, 367, 744 A.2d 649 (2000) the Court noted that equitable estoppel "may be invoked against a municipality 'where interests of justice, morality and common fairness clearly dictate that course.' " The Court noted further that equitable estoppel, though rarely invoked against a governmental entity, would be "applied in the appropriate circumstances unless the application would 'prejudice essential governmental functions.' " Id. at 367, 744 A.2d 649. The Middletown Court reaffirmed that actions that are ultra vires in the secondary sense would permit the application of estoppel. Middletown, 162 N.J. at 368, 744 A.2d 649. Because statutes provided for municipalities to extend health benefits to their retired employees, but not in the manner in which benefits were granted to the individual plaintiff in the Middletown case, the Court held that the action was ultra vires in the secondary sense. Id. at 369-71, 744 A.2d 649. The Court further held that "a municipality will be equitably estopped from terminating benefits that were previously approved and relied upon by the recipient." Id. at 372, 744 A.2d 649. Because the plaintiff had retired based on promises that he would receive post-retirement health benefits, and then he received the benefits for ten years before their provision was challenged by a third party, the municipality was equitably estopped from terminating the plaintiff's health benefits. Id. at 372-73, 744 A.2d 649.