46.—(1) The local returning officer must, immediately on receipt (whether by hand or by post) of a covering envelope (or an envelope which is stated to include a postal vote) before the close of the poll, place it unopened in a postal voters' ballot box.
(2) Where an envelope, other than a covering envelope issued by the local returning officer—
(a)has been opened, and
(b)contains a ballot paper envelope, postal voting statement or ballot paper,
the first-mentioned envelope, together with its contents, must be placed in a postal voters' ballot box.