Roosevelt Ordered Surveillance of Windsors

President Roosevelt personally ordered covert surveillance on the Duke and Duchess of Windsor during the second world war after receiving intelligence that the duchess had been passing secrets to a top Nazi with whom she was alleged to have had a tempestous affair, according to documents released to the Guardian by the FBI.

The damning dossier - released for the first time by the intelligence agency - shows that the main reason why the Americans thought the abdication of Edward VIII had taken place in 1936 was because the duchess fervently supported the Nazi regime and this was totally unacceptable to the then Conservative prime minister, Stanley Baldwin. The official view has always been that he abdicated to marry the person he loved but could not stay on the throne because she was a divorcee.

The papers show that the FBI was told by a minor German royal that Wallis Simpson was having an affair with Joachim von Ribbentrop, who was then German ambassador to Britain, while she was seeing the Duke of Windsor.

The minor royal, Duke Charles Alexander of Wurttemberg, who later became a Franciscan monk, said that "he knew definitely that von Ribbentrop, while in England, sent the then Wallis Simpson 17 carnations every day. The 17 supposedly represented the number of times they had slept together."

Later the FBI reported that while in exile in France, the duchess was in regular contact with von Ribbentrop, then promoted by Hitler to foreign minister, and was leaking secrets to him. They were then exiled again to the Bahamas.

The US intelligence operation began in 1941 when the couple came over from the Bahamas to spend a long weekend in Palm Beach, Florida, and were tailed by a FBI agent who had to fool both the Windsors and the US secret service on the orders of President Roosevelt. The FBI also reported that the duke was intoxicated and incapable for much of the time at the beginning of the war.

The papers also contain reports from a party in Paris that the duchess told guests that the duke was impotent and she was the only person who could satisfy his sexual desires.

The documents fuel the long-running controversy over allegations that the disloyal pair secretly admired fascism and that he was lined up to return to the throne if Hitler had conquered Britain.

The FBI first refused to release the documents to the Guardian but the paper appealed against the decision, and as a result 227 new pages - including intelligence reports of the operation and interviews with informants - have been disclosed.

The release comes at a sensitive time as the British public record office has not yet released similar documents which cover this period in deference to the sensibilities of the late Queen Mother.