Portugal: double taxation agreement, Article 23: Non-discrimination
(1) The nationals of a Contracting State shall not be subjected in the other Contracting State to any taxation or any requirement connected therewith which is other or more burdensome than the taxation and connected requirements to which nationals of that other State in the same circumstances are or may be subjected.
(2) The term `nationals` means:
(a) in relation to the United Kingdom:
(i) all citizens of the United Kingdom and Colonies other than those citizens who derive their status as such from connection with any territory to which this Convention may be extended under Article 27 but has not been so extended; (ii) all legal persons and associations deriving their status as such from the laws of the United Kingdom or any territory for whose international relations the United Kingdom is responsible to which this Convention is extended under Article 27;
(b) in relation to Portugal: all individuals possessing the nationality of Portugal and all legal persons and associations deriving their status as such from the laws of Portugal.
(3) The taxation on a permanent establishment which an enterprise of a Contracting State has in the other Contracting State shall not be less favourably levied in that other State than the taxation levied on enterprises of that other State carrying on the same activities.
(4) Enterprises of a Contracting State, the capital of which is wholly or partly owned or controlled, directly or indirectly, by one or more residents of the other Contracting State, shall not be subjected in the first-mentioned Contracting State to any taxation or any requirement connected therewith which is other or more burdensome than the taxation and connected requirements to which other similar enterprises of that first-mentioned State are or may be subjected.
(5) Nothing contained in this Article shall be construed as obliging either Contracting State to grant to individuals not resident in that State any of the personal allowances, reliefs and reductions for tax purposes which are granted to individuals so resident, nor as restricting the right of either Contracting State to tax in accordance with Article 10 dividends paid to a company which is a resident of the other Contracting State.