A breach of a non-molestation order is a criminal offence. If the respondent breaches the terms of the order, and the police are called, they may arrest the respondent and treat the breach in the same way as any other criminal offence. The maximum sentence for the offence is five years imprisonment, although the sentence for a first offender is obviously likely to be considerably less.
If the respondent breaches an occupation order then they will have to be brought back before the same court that made the order (rather than a criminal court, as in the case of breach of a non-molestation order) for contempt of court. The court may then fine them, impose a suspended sentence or commit them to prison, which would be rare for a first offence. If a power of arrest is attached to the occupation order, then the police may arrest the respondent and bring them back before the court. If there is no power of arrest, then the applicant will have to bring them back to the court, by making an application for their committal to prison. The applicant can also apply for a warrant for the respondent’s arrest.
Note that the respondent cannot both be guilty of a criminal offence and punished for contempt of court, in respect of the same conduct.