19.—(1) Subject to the First Schedule (which contains transitional provisions in respect of the leave years 1996 to 1998), an employee shall be entitled to paid annual leave (in this Act referred to as “annual leave”) equal to—
(a) 4 working weeks in a leave year in which he or she works at least 1,365 hours (unless it is a leave year in which he or she changes employment),
(b) one-third of a working week for each month in the leave year in which he or she works at least 117 hours, or
(c) 8 per cent. of the hours he or she works in a leave year (but subject to a maximum of 4 working weeks):