Some of the first part of Section 5 of the 1986 Public Order Act, dealing with threats and disorderly behaviour, seems perfectly reasonable and I don't think anyone is suggesting changing that. However, definitions of "abusive or insulting words" whether spoken or written will vary. That they become criminal if they are "within the hearing or sight of a person likely to be caused harassment, alarm or distress thereby" seems completely unreasonable, especially as there is no need to prove that someone actually was harassed, alarmed or distressed. Rudeness is not nice, but I don't think it should be a criminal offence.
The two most notorious arrests under Section 5 are that of a teenager outside Scientology Headquarters bearing a placard describing scientology as a cult and a student who called a policeman's horse gay. Charges were late dropped, but what a waste of time.
Section 5 was also used at a Hizb ut-Tahrir rally that was calling for Jews, apostates, gays and adulterous women to be killed. The people arrested under the Act were gay rights protesters outside protesting against incitement to murder.
This Act is not working properly and should be changed.