Britain's PM Cameron says Snowden files damaged national security LONDON (Reuters) - Britain's national security was damaged by the Guardian newspaper's publication of intelligence documents supplied by U.S. whistleblower Edward Snowden, Prime Minister David Cameron said on Wednesday. "The plain fact is that what has happened has damaged national security," Cameron told parliament. In many ways, the Guardian themselves admitted that when they agreed, when asked politely by my national security advisor and cabinet secretary, to destroy the files they had. Reporting by Peter Griffiths; Editing by Andrew Osborn