Social media mass surveillance is permitted by law, says top UK official

Anyone's Google searches or use of Facebook, Twitter and YouTube can be monitored by the security services because such "external communications" do not require individual intercept warrants, according to the government's most senior security official.

Charles Farr, director general of the Office for Security and Counter-Terrorism, has produced the first detailed justification of the UK's mass surveillance policy - developing a legal interpretation that critics say sidesteps the need for traditional intercept safeguards.

His 48 page document provoked calls for the Regulation of Investigatory Powers Act (RIPA) to be overhauled urgently and allegations that the government was exploiting loopholes in the legislation of which parliament was unaware.

The government defense was published in response to a case brought by Privacy International, Liberty, Amnesty International and other civil rights groups before the Investigatory Powers Tribunal (IPT), which deals with complaints against the intelligence services. A full hearing will take place in July. The allegation that mass online surveillance is illegal emerged in the wake of revelations from the US whistleblower Edward Snowden about the impact of the Tempora monitoring programme operated by the UK monitoring agency GCHQ and the US National Security Agency (NSA).