BT Broadband has admitted that it carried out secret trials on 18,000 user accounts in autumn 2006 with technology from 121Media, which became the targeted advertising company Phorm. Though BT has not yet said where the trials were done, the systems were used to analyse web traffic and then serve selected adverts on a number of selected websites.The revelation, first detailed on The Register website, might lead to legal action by any of the users who can show their data was used. That is because it appears to breach the Regulation of Investigatory Powers Act (RIPA) 2000, which makes it an offence to intercept internet traffic without consent or a warrant.
http://www.guardian.co.uk/technology/2008/apr/03/privacy.telecoms