151. (1) In this Regulation “night work” means work in the period between the hours of 11 p.m. on any day and 6 a.m. on the next following day where—

(a) the employee works at least 3 hours in that period as a normal course, or

(b) at least 25 per cent of the employee’s monthly working time is performed in that period.

(2) An employer shall—

(a) if a registered medical practitioner certifies that it is necessary for the safety or health of an employee that she should not be required to perform night work during pregnancy or for 14 weeks following childbirth not oblige her to perform night work during that period, and

(b) in a case to which subparagraph (a) relates—

(i) transfer the employee to daytime work, or

(ii) where such a transfer is not technically or objectively feasible on duly substantiated grounds, or both, grant the employee leave or extend the period of maternity leave.