LONDON -- The British government has begun releasing documents from Winston Churchill's secret wartime intelligence archive, but the papers have shed no light on one of the war's greatest mysteries: whether Churchill knew in advance of the Japanese attack on Pearl Harbor in December 1941.
One document, dated Dec. 4, three days before the attack, is a record of a message that had been sent Dec. 2 from the Japanese foreign minister in Tokyo to the Japanese ambassador in Washington ordering him to destroy secret documents, codes and related materials. Presumably, such a step would have been taken just before the outbreak of war.
It is clear that the message was intercepted, but a spokesman for the British Foreign Office said there was no indication whether the document was shared with the Americans. Historians have written extensively about the sharing among the wartime allies of intelligence derived from breaking the Japanese code.
A statement drawn up by the Public Record Office to accompany the first trickle of Churchill documents said: "None of the intercepts obviously indicate that British sources were aware in advance of the Japanese attack on Pearl Harbor, although it was clear that Japan was about to enter the war."
The statement added, however, that "it is possible that historians making a detailed examination of all the relevant material might draw a different conclusion."
A spokesman for the office said the statement alluded to the fact that archivists had not yet reviewed all 1,273 files containing the daily intelligence reports given to Churchill in 1941 and 1942, which are to become public information today. He said it did not suggest that anyone had unearthed a piece of paper that was ambiguous or that suggested Churchill knew and did not tell President Franklin D. Roosevelt about the plan for the attack.
In their 1991 book "Betrayal at Pearl Harbor," James Rusbridger and Eric Nave argue that British code-breakers based in Singapore at the British Far East Combined Bureau had cracked JN-25, the Japanese naval code, and thereby learned of the imminent attack on Pearl Harbor, the main U.S. naval base in the Pacific.
The authors contended that this information was withheld from the Americans, who were unaware that the British could read JN-25, because Churchill believed that a sneak attack would instantly smash isolationism in the United States and propel the nation into the war.
That hypothesis contradicts Churchill's account of how he learned of the Japanese attack. In the third volume of his war memoirs, "The Second World War," Churchill wrote that he was having dinner on Dec. 7 with John Winant, the U.S. ambassador, and W. Averell Harriman, Roosevelt's special envoy, when they turned on the news and heard "some few sentences" regarding "an attack by the Japanese on American shipping at Hawaii."
Churchill said he called Roosevelt and that the president replied, "It's quite true. They have attacked us at Pearl Harbor. We are all in the same boat now."
The prime minister wrote of sending messages around the world and of what he felt at the time: "No American will think it wrong of me if I proclaim that to have the United States at our side was to me the greatest joy."
The next day, British forces were overwhelmed when the Japanese landed in Malaya and Thailand and bombed Singapore. The Japanese quickly overran the Malay peninsula through a combination of land and air attacks, forcing Britain to pull its ships out of its vast naval base in Singapore and to surrender in February 1942.