4.1 The Economic Union shall constitute a customs union which shall cover all trade in goods eligible for Economic Union Tariff Treatment in accordance with Article 5 and which shall involve the prohibition between Protocol Member States of import duties, and the adoption of a common customs tariff in their relation with third countries.
4.2 For the purposes of this Article the term “import duties” means any tax or surtax of customs and any other charges of equivalent effect – whether fiscal, monetary or exchange – which are levied on imports, except duties notified under Article 7 and other charges which fall within that Article.
4.3 The provisions of this Article do not apply to fees and similar charges in respect of services rendered and nothing in paragraph 2 of this Article shall be construed to exclude from the application of paragraph 1 of this Article any tax or surtax of customs on any product neither the like of which, nor a competitive substitute for which, is produced in the importing Protocol Member State, or to extend such application to non-discriminatory internal charges on any such product.
4.4 For the purposes of paragraph 3 of this Article —
(a) “non-discriminatory” means non-discriminatory as between goods eligible for Economic Union Area tariff treatment as aforesaid and goods not so eligible;
(b) a charge shall not be deemed other than internal by reason only that it is collected at the time and place of importation.