Section 127 of the Communications Act

127 Improper use of public electronic communications network

(1)A person is guilty of an offence if he—

(a)sends by means of a public electronic communications network a message or other matter that is grossly offensive or of an indecent, obscene or menacing character; or

(b)causes any such message or matter to be so sent.

(2)A person is guilty of an offence if, for the purpose of causing annoyance, inconvenience or needless anxiety to another, he—

(a)sends by means of a public electronic communications network, a message that he knows to be false,

(b)causes such a message to be sent; or

(c)persistently makes use of a public electronic communications network.

(3)A person guilty of an offence under this section shall be liable, on summary conviction, to imprisonment for a term not exceeding six months or to a fine not exceeding level 5 on the standard scale, or to both.

(4)Subsections (1) and (2) do not apply to anything done in the course of providing a programme service (within the meaning of the Broadcasting Act 1990 (c. 42)).

[on the Australian section 474.17 of the Commonwealth Crimes Act] a carriage service to menace, harass or cause offense,' punishable by three years in jail."

Cause offense? Your existance offends me! Your funny-colored hair offends me! The fact that you're a man, woman, human, or bovine offends me! See, that's the problem with "cause offense" -- it's entirely subjective. It depends on the recipient. No free country should have a law on the books claiming things that are offensive are illegal, anymore than people should be liable for the emotional reactions of others. When you make something criminal, you need to be specific about the behavior. "Entered house with force and intent to steal." That's provable, objective, and fairly unambiguous. "Caused emotional distress" can't be proven, it's totally subjective, and highly ambiguous. In any criminal test, you have to ask yourself: Could a reasonable person determine ahead of time that the behavior in question was (unambiguously) illegal?