A file of correspondence concerning the erection of a wireless station at Toronto codenamed 'Hydra' in 1942, and plans to transfer that station from the Foreign Office to the Air Ministry the following year. Subjects covered in the file include the projected costs for the office buildings, accommodation, and equipment; Treasury concern over the cost of the living quarters; plans to compensate the Foreign Office for the transfer of the station to the Air Ministry from funds of the Secret Intelligence Service (MI6) and Special Operations Executive (SOE); and the abandonment of the transfer at the instigation of 'C'.