Karma Police (usually capitalised as KARMA POLICE) is the code name for an Internet mass surveillance and data collection programme operated by the United Kingdom's Government Communications Headquarters (GCHQ).
In 2015, documents obtained by The Intercept from U.S. National Security Agency whistleblower Edward Snowden revealed that GCHQ had carried out the KARMA POLICE operation since about 2008.
[1] The KARMA POLICE operation swept up the IP address of Internet users visiting websites.
KARMA POLICE is a powerful spying tool in conjunction with other GCHQ programs, because IP addresses could be cross-referenced with other data.
[1] The goal of the program, according to the documents, was "either (a) a web browsing profile for every visible user on the internet, or (b) a user profile for every visible website on the internet.