BT is facing an investigation by the Crown Prosecution Service (CPS) over allegations that its trials of the targeted online advertising system  from Phorm contravened privacy laws.

The CPS is investigating whether tests of the Phorm service by BT in 2006 and 2007, where BT did not ask customers' permission before running the tests, broke  the Regulation of Investigatory Powers Act (RIPA), which prohibits the interception of online data without consent.

Webwise is a feature currently offered to advertisers by a handful of UK mass-market ISPs – BT, Virgin Media and TalkTalk – between them accounting for around 70% of the UK broadband market.

Phorm says its system helps protect surfers from fraudulent websites, but, given that at the same time it replaces generic online ads with those directly relevant to a viewer's interests, some web users, including Berners-Lee, the founder of the World-Wide Web have deeper concerns.
In an interview with BBC News, Berners-Lee said that consumers need to be protected against systems which track activity on the internet, saying "I want to know if I look up a whole lot of books about some form of cancer, that it's not going to get to my insurance company and I'm going to find my insurance premium is going to go up by 5% because they've figured out [why] I'm looking at those books."