One of the most useful and most-used powers that criminal courts1 have is the power to bind people over to be of good behaviour or to keep the peace. Magistrates form the view that a person (“the principal”), who might be a person of previously unblemished reputation, is likely to breach the peace or commit criminal offences. They require him to enter into a recognisance, in form a voluntary covenant or agreement, to keep the peace, or to be of good behaviour, sometimes in a set sum (say £100) for a set period. If he refuses, he can be imprisoned, regardless of the seriousness or triviality, lawfulness or unlawfulness, of the behaviour that originally brought him to court, perhaps as a witness. He may also be required to find sureties, other people who are prepared to promise that they will forfeit a sum of money (say £50 each) if their principal fails to behave. If the principal misbehaves, debts to the Crown arise of £100 from the principal and £50 from each surety. The mechanics are therefore rather similar to bail. Binding over operates today in two ways. First, it can be used after conviction for an offence as an alternative to sentence. The accused enters into a recognisance to keep the peace or be of good behaviour. If he breaches his undertaking, he can be summoned back to court to be sentenced for the original offence. Secondly, it can be used after conviction for an offence as an alternative to sentence. The accused enters into a recognisance to keep the peace or be of good behaviour. If he breaches his undertaking, he can be summoned back to court to be sentenced for the original offence. Secondly, it can be used as a preventive measure to deal with people who are before the court but have not been convicted. This latter use provides a flexible way to deal with cases arising out of disputes between neighbours and minor public order problems without the need for a full hearing. It saves time and money.