DT: Sri Lanka: double taxation agreement, Article 25: Entry into force
This Convention shall come into force on the date on which the last of all such things shall have been done in the United Kingdom and Sri Lanka as are necessary to give the Convention the force of law in the United Kingdom and Sri Lanka respectively, and shall thereupon have effect:
(a) in the United Kingdom:
(i) as respects income tax and capital gains tax for any year of assessment beginning on or after 6th April, 1977;
(ii) as respects corporation tax, for any financial year beginning on or after 1st April, 1977,
(b) in Sri Lanka:
as respects Sri Lanka tax, for the year of assessment commencing on 1st April, 1977, and subsequent years of assessment.