§ 1. That any Act of the present Session relating to Finance may amend the provisions of Chapter II of Part XVIII of the Income Tax Act 1952, as to the circumstances in which income paid to or for the benefit of a child of a settlor is to be treated as income of the settlor and a settlement is to be treated as revocable and may add provisions to Chapter III of that Part for treating income arising under certain settlements as income of the settlor; and any such amendment or addition may have effect for surtax purposes for the year 1957–58 as well as subsequent years of assessment.