The Vetting and Barring scheme (ISA) aims to prevent unsuitable people from undertaking certain paid or volunteer work with children or vulnerable adults ('regulated activity'). It will do this by vetting all those who wish to do such work with vulnerable groups and barring those where the information shows the pose a risk of harm and (i due course) vetting those who with to do certain other types of work ('controlled activity').
For more detailed information visit the Independent Safeguarding Authority Website www.isa-gov.org.uk which explains;
Download - The Vetting and Barring Scheme Guidance March 2010