3.—(1) Any person who sends to another person—
(a)a letter or other article which conveys—
(i)a message which is indecent or grossly offensive;
(ii)a threat; or
(iii)information which is false and known or believed to be false by the sender; or
(b)any other article which is, in whole or part, of an indecent or grossly offensive nature,
is guilty of an offence if his purpose, or one of his purposes, in sending it is that it should, so far as falling within sub-paragraph (a) or (b), cause distress or anxiety to the recipient or to any other person to whom he intends that it or its contents or nature should be communicated.
(2) A person is not guilty of an offence by virtue of paragraph (1)(a)(ii) if he shows—
(a)that the threat was used to reinforce a demand which he believed he had reasonable grounds for making; and
(b)that he believed that the use of the threat was a proper means of reinforcing the demand.
(3) In this Article references to sending include references to delivering and to causing to be sent or delivered.
(4) A person guilty of an offence under this Article shall be liable on summary conviction to a fine not exceeding level 4 on the standard scale.