It is important to note that unlike the U.S., under European Union law IP Addresses are considered to be personal data as defined by article 2(a) of Directive 95/46/EC " 'personal data' shall mean any information relating to an identified or identifiable natural person ('data subject'); an identifiable person is one who can be identified, directly or indirectly, in particular by reference to an identification number or to one or more factors specific to his physical, physiological, mental, economic, cultural or social identity; " Also see Directive 2006/24/EC.

In association with time codes, IP Addressing information will always identify unique ISP account holders unless there is translation of that information.

It is important that this significant difference in legal status be understood, because Websites that provide for third-party interception of IP addressing information and traffic data, without Website visitor consent, are committing a criminal offence in the UK by virtue of the Regulation of Investigatory Powers Act 2000, where through the requirements of European Council Decision 2005/222/JHA such Website owners face serious sanctions, including the winding up of their businesses, being debarred from running a business, and more than 2 years imprisonment.

from http://en.wikipedia.org/wiki/IP_address#IP_address_legality_in_Europe

..so basically if you re-display any visitor data of IP addresses to your site without consent you are in breach of the Investigatory Powers Act..