The possession of indecent images of children is a serious criminal offence and must be reported to the Police as soon as possible. Until the material can be handed to the Police, organisations need to act very carefully to avoid harm to their users or potential criminal liability for the organisation or its staff. These JANET(UK) Guidelines, provide assistance in this situation.
http://www.ja.net/development/legal-and-regulatory/regulated-activities/soaguidelines.html