its title, the Public Order Act some offences which apply whether the takes place in a public or a private place. Of particular here are those offences which violence or the threat of violence. The Act provides a "ladder" of offences, of which the most serious is riot ( 1). The essence of riot is the use of unlawful violence by two or more persons in a group of at least twelve persons who are using or threatening violence. The penalty is ten years' imprisonment, compared with a of five years for the lesser offence of violent disorder. The essence of violent disorder ( 2) is the use or threat of unlawful violence in a group of at least three persons who are using or threatening violence. Beneath violent disorder comes the crime of affray ( 3), now in terms of threatening or using unlawful violence towards another, and carrying a of three years' imprisonment. Affray may be by one , and, like the other offences, it may be in a private place. The term "violence" includes intended to cause harm and which might cause harm (such as throwing a missile towards someone); and, for the two most serious offences of riot and violent disorder, "violence" bears an extended meaning which includes violent towards property.

Is it necessary to have an extra ladder of offences so closely with the general ladder of offences of violence? One reason might be the unsatisfactory state of the law under the Offences against the Person Act 1861: that Act fails to provide both a clear and defensible gradation of offences and any general offences of threatening violence against another. The provisions of the Public Order Act are, however, usually on other grounds. One supposed is that these extra offences are needed to cope with "group offending", which causes fear in ordinary citizens, and extra difficulties for the police and for prosecutors (in persuasive ). Offences by groups may well occasion greater fear than offences by , and it may also be true that groups have a tendency to do things which might not do: there is a group bravado, a group pressure, which may lead to excesses. On the other hand, the criminal law already makes some provision for such cases. The law of conspiracy is aimed at group offending, but conviction depends on proof of some agreement. The law of complicity the conviction of people who and abet others to offences, and spreads a fairly wide net in doing so.