Blogger fined for ‘menacing’ rant: “A man who ‘let off steam’ on his blog about police is convicted of posting a grossly offensive and menacing message.” The offender was fined £150 with £364 costs by magistrates at Mold.
Although it is not mentioned in the BBC article the offender must have been found guilty of section 127 of the Communications Act 2003.
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)).
DPP v. Collins ( EWHC 1308 (Admin)), A High Court decision sheds some light to what is being criminalized by section 127 of the Communications Act 2003.
“It is a longstanding peculiarity, but not an anomaly, that Parliament has criminalised the use of language which is not otherwise unlawful if it forms part of a message sent by post or by telephone – or, now, by any public electronic communications network: see section 127(1)(1A) of the Communications Act 2003. The reason, in essence, is that people are entitled to be protected from unsolicited messages which they may
find seriously objectionable.
The four classes of message which are proscribed are not of the same kind. A menacing message, fairly plainly, is a message which conveys a threat – in other words, which seeks to create a fear in or through the
recipient that something unpleasant is going to happen. Here the intended or likely effect on the recipient must ordinarily be a central factor in deciding whether the charge is made out. Obscenity and indecency, too, are generally in the eye of the beholder; but the law has historically treated them as a matter of objective fact to be
determined by contemporary standards of decency.
If (as I will assume) these are the respective meanings of menacing, obscene and indecent messages in the communications legislation, the category of grossly offensive messages can be seen to lie somewhere near the centre of the spectrum.
What is offensive has to be judged (very much as the justices, by considering the reaction of reasonable people, judged it) by the standards of an open and just multiracial society. So too, therefore, what is grossly offensive, an ordinary English phrase with no special legal content, which on first principles (see Brutus v Cozens  AC854) it is for the justices to apply to the facts as they find them. Whether a telephone message falls into this category has to depend not only on its content but on the circumstances in which the message has been sent and, at least as background, on Parliament’s objective in making the sending of certain messages a crime.
…it is not every transmission of grossly offensive language which is punishable, but only messages which, in their particular circumstances and context, are to be regarded in the wider society which the
justices represent as grossly offensive.”
DPP v. Collins reached the House of Lords:  UKHL 40 The offence is a necessary limitation on everyone’s right to freedom of expression, the House of Lords has ruled.