One way a t is legally/morally required to be under a duty to report knowledge of abuse to other authorities in the UK is where the abuser is known to be a medic, nurse, allied healthcare worker, teacher etc. It is about DBS checks and Protection of the Vulnerable surrounding "Regulated Activity". "Regulated Activity" includes a person working closely with vulnerable people in intimate situations or the worker having power over vulnerable people's lives.
The CQC and OFSTED respectively monitor health and education/adoption services in the UK. Providers of psychology services have to be registered with the CQC (so do GP surgeries). The service provider who supplies/recommends a t to work with a csa victim would require the t to report known/suspected abusers. If a t chooses not to report such an abuser then that t's professional conduct could be called into question at some point - effectively non disclosure equates to the t aiding and abetting the said abuser to continue to commit more csa crimes.
Every Local Authority in England has to have a Safeguarding of the Vulnerable Team. This Team investigates and monitors the abuse of vulnerable children and adults. Safeguarding Teams include in their workforce Specialist Social Workers and Police representatives. Such teams have the responsibility of keeping the vulnerable safe and this sometimes includes prosecuting offenders and maintaining POVA Lists of Abusers who should not be granted a DBS certificate to work with vulnerable people.
The whole system does not only include monitoring employees in the strictest sense of the word, it includes monitoring volunteers who work in charities, clubs, schools, care etc.
