Clause 24

Every ballot box shall be so constructed that the ballot papers can be introduced therein but cannot be withdrawn therefrom unless the box is unlocked.

The presiding officer at a polling station shall, immediately before the commencement of the poll, show each ballot box to be used at the commencement of the poll empty to such person (if any) as may be present in the station so that the person may see that it is empty, and shall then lock it up and place his seal upon it in such manner as to prevent it being opened without breaking the seal, and shall place it in his view for the receipt of ballot papers and keep it so locked and sealed.

Subsection (2) shall apply to every ballot box used during a poll and it shall be sufficient compliance with that subsection if a ballot box, other than a ballot box used at the commencement of a poll, is shown, locked up and sealed in accordance with that subsection before it is used.