2(1)Subject to sub-paragraph (2), regulations may enable the Board to determine in prescribed circumstances that an earner, or any group of earners whose employment falls within a particular category or description of contracted-out employments, has been in such employment from a date (“the determined date”) earlier than would otherwise be the case.E+W+S
(2)The determined date for any earner may not be earlier than—
(a)the date on which his relevant employment began, or
(b)the date on which a contracting-out certificate was issued in respect of it,
whichever is the later.