Y-stations were British Signals Intelligence collection sites initially established during World War I and later used during World War II. These sites were operated by a range of agencies including the Army, Navy and RAF plus the Foreign Office (MI6 and MI5), General Post Office and Marconi Company receiving stations ashore and afloat. The term was also used for similar stations attached to the Intelligence Corps' India outpost, the Wireless Experimental Centre (W.E.C.) outside Delhi.