(1) Subject to the following paragraphs and the provisions of Articles 7 to 10, where a person is gainfully employed, liability for contributions for him shall be determined under the legislation of the Party in whose territory he is so employed.
(2) Where a person is employed in the territory of both Parties for the same period, liability for contributions for him shall be determined only under the legislation of the Party in whose territory he is ordinarily resident.
(3) Where a person is self-employed in the territory of both Parties for the same period, liability for contributions for him shall be determined only under the legislation of the Party in whose territory he is ordinarily resident.
(4) Where a person is employed in the territory of one Party and self-employed in the territory of the other Party for the same period, liability for contributions for him shall be determined only under the legislation of the former Party.
(5) No provision of this Article shall affect a person’s liability to pay a Class 4 contribution under the legislation of the United Kingdom.
(6) Where a person is not gainfully employed, any liability for contributions shall be determined under the legislation of the Party in whose territory he is resident.
(7) Where, but for the provisions of this paragraph, a person would be entitled to pay contributions voluntarily under the legislation of both Parties for the same period, he shall be entitled to pay contributions only under the legislation of one Party according to his choice.
(8) Where under the provision of Articles 7, 8(a) or (b), a person is employed in the territory of one Party while remaining liable for contributions under the legislation of the other Party, the legislation of the former Party shall not apply to him and he shall not be liable, nor entitled, to pay contributions under the legislation of the former Party.
(9) Where a person is gainfully employed in the territory of one Party and the legislation of the other Party does not apply to him in accordance with the provisions of paragraphs (1) and (4), or ceases to apply to him under Articles 7, 8(a) or (b), the legislation of the former Party shall apply to him as if he were ordinarily resident in the territory of that Party.