7.—(1) Subject to regulation 27, the operator of a production installation shall ensure that it is not operated unless—
(a)he has prepared a safety case containing the particulars specified in regulation 12 and Schedule 2;
(b)he has sent the safety case to the Executive at least 6 months (or such shorter period as the Executive may specify) before commencing the operation; and
(c)the Executive has accepted the safety case.
(2) For the purposes of paragraph (4) of regulation 2 and paragraph (1), the operation of an installation shall be treated as commenced—
(a)on the commencement of the first well drilling operation from the installation which may involve the release of petroleum from beneath the sea-bed; or
(b)when petroleum is brought onto the installation for the first time through a pipeline or well,
whichever is earlier.
(3) A safety case prepared pursuant to paragraph (1) and revisions to a current safety case prepared pursuant to regulation 9(5) may be prepared in relation to more than one production installation where the Executive so approves in writing and, where a safety case is or revisions are to be so prepared in relation to installations with different operators, it shall be sufficient compliance with paragraph (1)(a) and (b) and regulation 9(5)(a) and (b) if the operators prepare and agree a safety case or revisions containing the particulars referred to in that paragraph and that regulation and one of them sends it to the Executive in accordance with paragraph (1)(b) and regulation 9(5)(b).