JURISDICTION BY ESTOPPEL

                The operation of estoppel on the question of jurisdiction seemingly depends on whether the lower court actually had jurisdiction or not.   If it had no jurisdiction, but the case was tried and decided upon the theory that it had jurisdiction, the parties are not barred, on appeal, from assailing such jurisdiction, for the same "must exist as a matter of law, and may not be conferred by the consent of the parties or by estoppel."   However, if the lower court had jurisdiction, and the case was heard and decided upon a given theory, such, for instance, as that the court had no jurisdiction, the party who induced it to adopt such theory will not be permitted, on appeal, to assume an inconsistent position – that the lower court had jurisdiction” (Lozon v. NLRC 310 Phil. 1 1995 cited in ATTY. RESTITUTO G. CUDIAMAT, et al. vs. BATANGAS SAVINGS, et al., G.R. No. 182403, March 9, 2010, First Division, Carpio Morales, J.).