In July 1940, Britain had offered to give the United States access to its scientific research, and the Tizard Mission's John Cockcroft briefed American scientists on British developments. He discovered that the American S-1 Project (later renamed the Manhattan Project) was smaller than the British, and not as far advanced. The British and American projects exchanged information, but did not initially combine their efforts. British officials did not reply to an August 1941 American offer to create a combined project. In November 1941, Frederick L. Hovde, the head of the London liaison office of the American Office of Scientific Research and Development (OSRD), raised the issue of cooperation and exchange of information with Anderson and Lord Cherwell, who demurred, ostensibly over concerns about American security. Ironically, it was the British project that had already been penetrated by atomic spies for the Soviet Union.