Taking account of the general principles of prevention in Schedule 3 to the Act, an employer shall -
(a) ensure that work is not carried out at height where it is reasonably practicable to carry out the work safely and without risk to health otherwise than at height,
(b) without prejudice to the generality of paragraph (a), ensure that work is not carried out at height unless it is reasonably practicable to do so safely and without risk to health,
(c) where, having regard to paragraphs (a) and (b), it is necessary to carry out work at height, take suitable and sufficient measures to prevent an employee falling a distance liable to cause personal injury, including -
(i) ensuring that the work is carried out -
(I) from an existing place of work, or
(II) in the case of obtaining access or egress, by using an existing means of access or egress,
in compliance with this Part, where it is practicable to do so safely and under appropriate ergonomic conditions, and
(ii) where it is not practica
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