The intelligence services are constructing “vast databases” out of accumulated interceptions of emails, a tribunal investigating mass surveillance of the internet has been told.The claim emerged during a ground-breaking case against the monitoring agency GCHQ, MI5, MI6 and the government at the investigatory powers tribunal (IPT).
http://www.theguardian.com/uk-news/2014/jul/18/intelligence-services-email-database-internet-tribunal