Section 170

Any person who knowingly sends, or attempts to send, by post anything which-

(a) encloses anything, whether living or inanimate, of such a nature as to be likely to injure any other thing in the course of conveyance, or to injure any person; or

(b) encloses an indecent or obscene print, painting, photograph, lithograph, engraving, book, card, or article, or which has on it, or in it, or on its cover, any indecent, obscene, or grossly offensive words, marks, or designs;

is guilty of a misdemeanour, and is liable to imprisonment for one year.