Subsequently , on 4 November 2015 , the Home Secretary announced that after the September 11 attacks in the U.S. , MI5 started collecting bulk telephone communications data on which telephone numbers called each other and when , under a section 94 direction instead of the Regulation of Investigatory Powers Act 2000 which would have brought independent oversight and regulation . This had been kept secret until announced in 2015 , without laying the direction before parliament under the against the interests of national security exemption
September 11 attacks
September 11 attacks
Telecommunications Act 1984