18.—(1) A person who in any public place uses—
(a)F1. . . disorderly behaviour; or
(b)behaviour whereby a breach of the peace is likely to be occasioned,
shall be guilty of an offence.
(2) A person guilty of an offence under paragraph (1) shall be liable on summary conviction to imprisonment for a term not exceeding 6 months or to a fine not exceeding level 5 on the standard scale, or to both.
[F1(3) A person who in any public place uses riotous behaviour shall be guilty of an offence.
(4) A person guilty of an offence under paragraph (3) shall be liable on summary conviction to imprisonment for a term not exceeding 12 months or to a fine not exceeding level 5 on the standard scale or to both.]