Section 357I | The Northern Ireland rate
From legislation.gov.uk
(1)The Northern Ireland rate for a financial year is—
(a)if a resolution of the Northern Ireland Assembly—
(i)sets a rate under section 357IA for the year, and
(ii)is passed before the beginning of the year,
the rate set by the resolution;
(b)if the Northern Ireland rate for the year is not determined under paragraph (a), but the Northern Ireland rate for one or more earlier financial years was determined under that paragraph, the rate for the most recent of those earlier years;
(c)otherwise, the main rate.
(2)For the purposes of subsection (1)(a)(ii), a resolution passed before the beginning of a financial year is treated as not having been so passed if it is cancelled by a resolution under section 357IA that is itself passed before the beginning of the year.