5Earnings limits for Class 1 contributions
(1)For the purposes of this Act there shall for every tax year be—
(a)a lower earnings limit for Class 1 contributions, being the level of weekly earnings at which employed earners become liable for such contributions in respect of the earnings from their employments; and
(b)an upper earnings limit for Class 1 contributions, being the maximum amount of weekly earnings in respect of which primary Class 1 contributions are payable;
and those limits shall be the amounts specified for that year by regulations made in accordance with subsections (2) and (3) below.
(2)The amount specified as the lower earnings limit for any tax year shall be an amount equal to or not more than 99p less than—
(a)the sum which at the beginning of that year is specified in section 44(4) below as the weekly rate of the basic pension in a Category A retirement pension; or
(b)that sum as increased by any Act or order passed or made before the beginning of that year and taking effect before 6th May in that year.
(3)The amount specified as the upper earnings limit for any tax year shall be an amount which either—
(a)is equal to 7 times the sum by reference to which the lower earnings limit for that year is specified in accordance with subsection (2) above; or
(b)exceeds or falls short of 7 times that sum by an amount not exceeding half that sum.