4 Fear or provocation of violence.
(1) A person is guilty of an offence if he—
(a)causes towards another person threatening, abusive or insulting words or behaviour, or
(b)distributes or displays to another person any writing, sign or other visible representation which is threatening, abusive or insulting,
with intent to cause that person to believe that immediate unlawful violence will be used against him or another by any person, or to provoke the immediate use of unlawful violence by that person or another, or whereby that person is likely to believe that such violence will be used or it is likely that such violence will be provoked.
Here is the main part of Sec 4 POA, notice the word 'or' placed in the definition and how simply it could fit most disorders in a public place.
Here is subsection (4) of the act
(4) 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.
(I believe a level 5 fine is £5000)