WebMinder
WebMinder is a content blocking system implemented in the UK by Brightview Internet Services and used on their ISPs such as Madasafish, Global Internet and Waitrose.Com. It is similar in purpose to Cleanfeed, BT's blocking system and uses a list from the Internet Watch Foundation. In addition to this it claims to stop images from these sites being transmitted as email attachments. [1]
Brightview say that WebMinder is available for any UK internet provider for free. However the ISPs it lists as using the technology are all owned by Brightview.