"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 (c) that his conduct was reasonable"
"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."