20.—(1) Subject to paragraph (2) and to any provisions imposed by the Communities in respect of the control and regulation of genetically modified organisms, the Executive may, with the agreement of the Secretary of State in so far as the exemption relates to the environment, by a certificate in writing, exempt any person or class of persons, genetically modified organism or class of genetically modified organisms from all or any of the requirements or prohibitions imposed by these Regulations and any such exemption may be granted subject to conditions and to a limit of time and may be revoked by a certificate in writing at any time.
(2) The Executive shall not grant any such exemption unless, having regard to the circumstances of the case and in particular to—
(a)the conditions, if any, that it proposes to attach to the exemption; and
(b)any requirements imposed by or under any enactments which apply to the case,
it is satisfied that the health and safety of persons who are likely to be affected by the exemption or the protection of the environment will not be prejudiced in consequence of it.