Summary: Constitution of Pakistan, 1973--- ----Arts. 8, 10A, 175F, 199, 202A & Third Schedule---Income Tax Ordinance, 2001, S. 109-A---Constitution (Twenty-Sixth Amendment) Act, 2024---Constitution (Twenty-Seventh Amendment) Act, 2025---Challenge to vires of statutory provision---Jurisdiction of Constitutional Bench vis-à-vis Regular Bench under erstwhile Art. 202A---Dominant object theory---Ad-interim order suspending operation of law---Maintainability of challenge thereto---Petitioner, after availing 2018 Amnesty Scheme and declaring ownership of foreign company, was issued notice under S.109-A, Income Tax Ordinance, 2001---He challenged both vires of said provision and the notice issued thereunder before Sindh High Court, which initially granted ad-interim restraint against passing of any final adverse order---Later, Constitutional Bench of High Court recalled said interim order on ground that courts ought not suspend operation of law, particularly in revenue matters---Before Federal Constitutional Court, principal question was whether Constitutional Bench, under erstwhile Art. 202A, possessed jurisdiction to entertain matter whose dominant relief was declaration that impugned law was ultra vires---Held, challenge to vires of statute, in substance, sought relief under Art.199(1)(a)(ii), namely declaration that law was “without lawful authority” and “of no legal effect”, and not merely a direction under Art.199(1)(a)(i) or enforcement of fundamental rights simpliciter---Under pre-27th Amendment regime, such matter did not fall within exclusive jurisdiction of Constitutional Bench---Only forum competent to grant final relief could competently grant interim relief; therefore, Constitutional Bench lacked jurisdiction from the outset and its order recalling the earlier ad-interim order was without jurisdiction---Court further held that ad-interim order which had effect of suspending operation of law could validly be brought in challenge before this Court, as until law is finally declared ultra vires it must ordinarily continue to operate---However, in view of subsequent constitutional amendment, exclusive writ jurisdiction now vests in Constitutional Benches and similar matters would henceforth lie before such Benches---Matter was remanded to Sindh High Court for fresh decision by competent Bench in accordance with law. Kh. Muhammad Fazil v. Mumtaz Munnawar Khan Niazi (deceased) through legal heirs (2024 SCMR 1059); Attock Cement case (2024 SHC 1302); Benazir Bhutto v. Federation of Pakistan (PLD 1988 SC 416); Rahim Shah v. Chief Election Commissioner (PLD 1973 SC 24); Federation of Pakistan v. Aitzaz Ahsan (PLD 1989 SC 61); Marbury v. Madison (5 U.S. 137 (1803)) rel. (a) Constitution of Pakistan, 1973---Art. 202A (as it stood before Twenty-Seventh Amendment)---Jurisdiction of Constitutional Benches of High Courts---Scope--- Under erstwhile Art.202A, Constitutional Benches were not vested with entire writ jurisdiction under Art.199 but only with limited classes of matters specified therein---Therefore, question whether matter was to be heard by Constitutional Bench or Regular Bench had to be determined by reference to true nature of relief claimed. (b) Constitutional jurisdiction---Dominant object theory---Application--- For determining proper forum under former Art.202A, Court must examine pleadings, prayer clause and ultimate effect of relief sought so as to ascertain dominant or substantive relief, while treating merely consequential relief as ancillary---Such exercise is judicial in nature and not dependent upon drafting alone. (c) Challenge to vires of statute---Nature of relief--- Where petitioner assails validity of statutory provision and seeks declaration that same is contrary to Constitution, dominant relief is one under Art.199(1)(a)(ii), namely that impugned law is “without lawful authority” and “of no legal effect”---Such relief is, in substance, in nature of certiorari / declaratory judicial review, even if consequential directions are also sought. (d) High Courts---Power of judicial review---Inherent constitutional authority--- Power of High Court to strike down law ultra vires Constitution is inherent in constitutional scheme and flows from its role as guardian of Constitution, read with judicial oath and constitutional supremacy---Such authority is not negated merely because relief of declaration is not textually set out in identical terms in every clause of Art.199. (e) Interim relief---Competence of forum--- Interim relief may only be granted by forum competent to render final decision on lis---Consequently, where Constitutional Bench lacked jurisdiction to decide vires challenge under former Art.202A, it also lacked competence to pass or recall interim orders in relation thereto. (f) Ad-interim order suspending operation of law---Propriety and challenge thereto--- As a general constitutional principle, until a law is finally declared ultra vires, it should ordinarily continue to operate in normal course---An interim order having effect of suspending operation of law, especially in revenue matters, is therefore open to challenge before this Court and cannot be shielded merely because it is ad-interim in form. (g) Twenty-Seventh Constitutional Amendment---Effect--- After enactment of Constitution (Twenty-Seventh Amendment) Act, 2025, exclusive writ jurisdiction under Art.199 now lies with Constitutional Benches of High Courts, and Regular Benches no longer possess such jurisdiction---Accordingly, a case of like nature would now fall to be heard by Constitutional Bench. (h) Remand---When warranted--- Where impugned order has been passed by a Bench lacking jurisdiction, proper course is to set aside such order and remit matter for fresh adjudication by competent Bench in accordance with law. Petition allowed; impugned order set aside; matter remanded for decision by competent Bench of Sindh High Court in accordance with law.