The criminal justice system
Contains agencies of social controls with formal power to impose legal sanctions:
The police - powers to stop, search, arrest, detain, question.
The CPS - can charge a suspect and prosecute.
Judges and magistrates - bail or reman in custody, sentence.
HMPS - detain inmates, punish them for misbehaviour.
There are also positive sanctions - assisting the prosecution is likely to give a lower sentence.