This is the one ("POA s5") typically used against naturists where there is no accusation of sexual behaviour. The other sections of this Act refer to violent behaviour of one sort or another; section 5 requires only "disorderly" behaviour.
Part I
Section 5
Harassment, alarm or distress.
(1) A person is guilty of an offence if he -
(a) uses threatening, abusive or insulting words or behaviour, or disorderly behaviour, or
(b) displays any writing, sign or other visible representation which is threatening, abusive or insulting,
within the hearing or sight of a person likely to be caused harassment, alarm or distress 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 writing, sign or other visible representation is displayed, by a person inside a dwelling and the other person is also inside that or another dwelling.
(3) It is a defence for the accused to prove -
(a) that he had no reason to believe that there was any person within hearing or sight who was likely to be caused harassment, alarm or distress, or
(b) that he was inside a dwelling and had no reason to believe that the words or behaviour used, or the writing, sign or other visible representation displayed, would be heard or seen by a person outside that or any other dwelling, or
(c) that his conduct was reasonable.
The following 2 sections were repealed by the Serious Organised Crime and Police Act 2005 (c15) (in Schedule 17, implemented by Commencement No 4) and presumably replaced by something else:
(4) A constable may arrest a person without warrant if -
(a) he engages in offensive conduct which a constable warns him to stop, and
(b) he engages in further offensive conduct immediately or shortly after the warning.(5) In subsection (4) "offensive conduct" means conduct the constable reasonably suspects to constitute an offence under this section, and the conduct mentioned in paragraph (a) and the further conduct need not be of the same nature.
(6) A person guilty of an offence under this section is liable on summary conviction to a fine not exceeding level 3 on the standard scale.
Section 6 has some clauses that refer back to section 5:
Section 6.
Mental element: miscellaneous.
(1) A person is guilty of riot only if he intends to use violence or is aware that his conduct may be violent.
(2) A person is guilty of violent disorder or affray only if he intends to use or threaten violence or is aware that his conduct may be violent or threaten violence.
(3) A person is guilty of an offence under section 4 only if he intends his words or behaviour, or the writing, sign or other visible representation, to be threatening, abusive or insulting, or is aware that it may be threatening, abusive or insulting.
(4) A person is guilty of an offence under section 5 only if he intends his words or behaviour, or the writing, sign or other visible representation, to be threatening, abusive or insulting, or is aware that it may be threatening, abusive or insulting or (as the case may be) he intends his behaviour to be or is aware that it may be disorderly.
(5) For the purposes of this section a person whose awareness is impaired by intoxication shall be taken to be aware of that of which he would be aware if not intoxicated, unless he shows either that his intoxication was not self-induced or that it was caused solely by the taking or administration of a substance in the course of medical treatment.
(6) In subsection (5) "intoxication" means any intoxication, whether caused by drink, drugs or other means, or by a combination of means.
(7) Subsections (1) and (2) do not affect the determination for the purposes of riot or violent disorder of the number of persons who use or threaten violence.
There is a trap in s6(4) in the "...or is aware that it may be..." clause. It's not a good idea to say you were observing the reactions to your behaviour, that can be twisted to imply that you were aware there might be adverse reactions. Better to assume, quite reasonably, that no-one would be threatened, abused or insulted, and that there was no reason why the behaviour should be regarded as disorderly. Then, presumably, intention would have to be proved.
There is also a section 4A (added later) which is quite similar to section 5 but includes intention and actual harassment:
Section 4A
Intentional harassment, alarm or distress.
(1) A person is guilty of an offence if, with intent to cause a person harassment, alarm or distress, he—
(a) uses threatening, abusive or insulting words or behaviour, or disorderly behaviour, or
(b) displays any writing, sign or other visible representation which is threatening, abusive or insulting, thereby causing that or another person harassment, alarm or distress.(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 writing, sign or other visible representation is displayed, by a person inside a dwelling and the person who is harassed, alarmed or distressed is also inside that or another dwelling.
(3) It is a defence for the accused to prove—
(a) that he was inside a dwelling and had no reason to believe that the words or behaviour used, or the writing, sign or other visible representation displayed, would be heard or seen by a person outside that or any other dwelling, or
(b) that his conduct was reasonable.(4) A constable may arrest without warrant anyone he reasonably suspects is committing an offence under this section.
(5) A person guilty of an offence under this section is liable on summary conviction to imprisonment for a term not exceeding 6 months or a fine not exceeding level 5 on the standard scale or both.