BRITAIN has been forced to withdraw intelligence agents from operations because Russia and China have obtained access to secret information in files stolen by US whistleblower Edward Snowden, senior government sources have indicated. The ex-National Security Agency contractor - now in Russia - has insisted that crucial data in the material could not be accessed by foreign powers but UK security chiefs have warned that his actions had compromised anti-terror activity. In what was described by former GCHQ director Sir David Omand as a "huge strategic setback" for the West, it was reported that[...]