British Security Coordination British Security Coordination ( BSC ) was a covert organization set up in New York City by the British Secret Intelligence Service ( MI6 ) in May 1940 upon the authorization of Prime Minister Winston Churchill . Its purpose was to investigate enemy activities , prevent sabotage against British interests in the Americas , and mobilize pro - British opinion in the Americas . Beginnings . The declaration of war upon Germany by the British in September 1939 forced a break in liaison between SIS and the FBI , due to the US neutrality policy . William Stephenson was sent to the US by the head of SIS to see if it could be rekindled to an extent that SIS could operate effectively in the US . While J . Edgar Hoover was sympathetic he could not go against the State Department without the President ' s authorisation ; he also believed that if so authorised , it should be a personal liaison between Stephenson and himself without other departments being informed . In the event Roosevelt did endorse the cooperation . The liaison was necessary because Britain ' s enemies were already present in the States and could expect sympathy and support from German and Italian immigrants but the authorities there had no remit nor interest in activities that were not directly against US security . Stephenson ' s report on the American situation advocated a secret organization acting beyond purely SIS activities and covering all covert operations that could be done to ensure aid to Britain and an eventual entry of the US into the war . Stephenson was given this remit and the traditional cover of appointment as a ' Passport Control Officer ' which he took up in June 1940 . Although the existing setup in New York was lacking , in Stephenson could call upon his personal liaison with Hoover , the support of Canada , the British Ambassador , and his acquaintances with US interventionists . Operation . The office , which was established for intelligence and propaganda services , was headed by Canadian industrialist William Stephenson . Its first tasks were to promote British interests in the United States , counter Nazi propaganda , and protect the Atlantic convoys from enemy sabotage . The BSC was registered by the State Department as a foreign entity . It operated out of offices in Rockefeller Center , and was officially known as the British Passport Control Office from which it had expanded . BSC acted as administrative headquarters more than operational one for SIS and Special Operations Executive ( SOE ) and was a channel for communications and liaison between US and British security and intelligence organizations . BSC used a number of legitimate outlets for its work . In 1940 , a German agent - Weldrick - who was cultivating support and possible sabotage among American oil companies , was effectively exposed through news articles placed in the " New York Herald Tribune " . a wave of public outrage was followed by Weldrick ' s expulsion from the US and the forced resignation of the head of Texaco . Through third parties , BSC developed the independent and non - profit WRUL shortwave radio station foreign - language broadcast capability and then fed it stories it wanted disseminated worldwide . That the station had a large number of listeners who corresponded with the station made it possible for reactions to the broadcasts to be directly monitored . For a period the station was unwittingly , the agent of BSC ; after the US entered the war , the WRUL operation was turned over to US control . It was through the BSC , that the British acquired the powerful " Aspidistra " transmitter that was used for propaganda by the Political Warfare Executive ( PWE ) , BBC overseas broadcasts and the RAF in the war against Germany . BSC also sourced a transmitter for it to communicate with the UK which was operated under the code name " Hydra " at BSC ' s training school - Camp X - in Whitby , Ontario . Prior to , and after the entry of the US into the war , Camp X was used to train US personnel . Although the British and Americans were cooperating at the Prime Minister - President level at the time , the arrival of " British spies " in the United States infuriated J . Edgar Hoover , the director of the Federal Bureau of Investigation ( FBI ) , and displeased the U . S . Department of State . Despite the fact that Stephenson and Hoover did not see eye to eye , they had cooperated in a number of operations against espionage activities by Nazi Germany in the U . S . Although they also agreed that the British would not hire Americans , the BSC did the contrary . The Americans who were recruited in the BSC were given British identification numbers beginning with the digits 4 and 8 , apparently representing the 48 states . The British novelist William Boyd , in a 2006 article for " The Guardian " , stated that although the total number of BSC agents operating in the USA is unknown , he estimated the number to be at least " many hundreds " and had seen " the figure of up to 3 , 000 mentioned " . Noël Coward saw Stephenson , colloquially known as " Little Bill " , at the end of July 1940 when on a world entertainment and propaganda tour . He wrote that the " suite in the Hampshire House with the outsize chintz flowers crawling over the walls became pleasantly familiar to me . . . " and that Stephenson " had a considerable influence on the next few years of my life " . Stephenson offered him a job , but this was vetoed by London . Counter - smuggling and " shipping security " . South America was an important neutral source of trade for the Axis forces ; its importance would increase after the US entered the war . The Italian airline LATI operated a transatlantic service between Rome and Rio de Janeiro ( Brazil ) which was a conduit for high value goods ( platinum , mica , diamonds etc . ) , agents and diplomatic bag s . London instructed BSC to do something about . The Brazilian government had connections to the airline through the President ' s son - in - law and it was supplied - despite the US State Department protests - by Standard Oil in the US making official channels ineffective . To curtail its activities , BSC decided that it had to be closed down by the Brazilians themselves ; sabotage would be only a temporary inconvenience . To this end BSC constructed a forged letter of such accuracy that its authenticity could not be questions even under forensic examination . The letter purported to come from LATI ' s head office to an executive of the company stationed in Brazil . The contents included disparaging references to the Brazilian president and the US and implied connections with an anti - government fascist party . A " burglary " of the executive ' s house was followed by a photostat of the letter being placed with an American Associated who immediately took it to the American Embassy . The Embassy then showed the letter to President Vargas and as a result LATI ' s operations in Brazil were confiscated , and its personnel interned . Subsequently Brazil broke off relations with the Axis to join the Allies . To counter the carrying of high value contraband goods to and from the Americas , BSC set up a network of observers on merchant ships . These agents were recruited from the crews ( and pro - British masters ) of the vessel and would report their observations , cargo manifest s and passenger list s , to agents in port when they arrived . Together with agents watching docks at either end intelligence was gathered and ships or enemy agents could be intercepted while questionable crew blacklisted from employment by US and British lines . From autumn 1941 , the BSC handed over control of observers on American vessels and ports to the US while retaining control of the remainder and close liaison with the new US handlers .