Air traffic controllers issued a notice directed to air missions (Notam) on Thursday prohibiting drone operations below 2,500ft (760 metres) in a  radius of  2.5-mile from central part of London “for security reasons” to ensure protection of king’s coronation. The action was taken a couple of days after two unmanned aircrafts, in all likelyhood, deployed by pro-Ukrainian groups, were operated over presidential offices at the Kremlin in Moscow.