18 Use of words or behaviour or display of written material.
(1)A person who uses threatening, abusive or insulting words or behaviour, or displays any written material which is threatening, abusive or insulting, is guilty of an offence if—
(a)he intends thereby to stir up racial hatred, or
(b)having regard to all the circumstances racial hatred is likely to be stirred up thereby.
(2)An offence under this section may be committed in a public or a private place, except that no offence is committed where the words or behaviour are used, or the written material is displayed, by a person inside a dwelling and are not heard or seen except by other persons in that or another dwelling.
(3)A constable may arrest without warrant anyone he reasonably suspects is committing an offence under this section.
(4)In proceedings for an offence under this section it is a defence for the accused to prove that he was inside a dwelling and had no reason to believe that the words or behaviour used, or the written material displayed, would be heard or seen by a person outside that or any other dwelling.
(5)A person who is not shown to have intended to stir up racial hatred is not guilty of an offence under this section if he did not intend his words or behaviour, or the written material, to be, and was not aware that it might be, threatening, abusive or insulting.
(6)This section does not apply to words or behaviour used, or written material displayed, solely for the purpose of being included in a programme [F1included in a programme service].