A person who publishes or distributes written material which is threatening, abusive or insulting is guilty of an offence if—
he intends thereby to stir up racial hatred, or
having regard to all the circumstances racial hatred is likely to be stirred up thereby.
In proceedings for an offence under this section it is a defence for an accused who is not shown to have intended to stir up racial hatred to prove that he was not aware of the content of the material and did not suspect, and had no reason to suspect, that it was threatening, abusive or insulting.
References in this Part to the publication or distribution of written material are to its publication or distribution to the public or a section of the public.