The mass disclosure of the Edward Snowden files has "done considerable damage" to national security in a number of countries, a former terror laws watchdog has said.

Lord Carlile's comments come two years after the first press reports based on files leaked by Snowden, an ex-National Security Agency (NSA) worker.

The Lib Dem peer, a former independent reviewer of terrorism legislation, said: "I am absolutely certain that the way in which the Snowden cache was revealed has done considerable damage to the national security of numerous countries.