(1) A constable may give directions to the occupier of any relevant premises requiring him to take such measures to ensure the security of any dangerous substance kept or used there as are specified or described in the directions by a time so specified.
(2) The directions may-
(a) specify or describe the substances in relation to the security of which the measures relate; and
(b) require the occupier to give a notice to the chief officer of police before any other dangerous substance specified or described in the directions is kept or used in the premises.