Officials were pessimistic about the effectiveness of the atomic plans, however. Britain's December 1948 SPEEDWAY plan assumed that the Soviets would not have atomic weapons, but nonetheless forecast that the West could not "withstand a Russian advance in Western Europe, even with the full defence co-operation of the Western Powers", including 560 American and British atomic-capable bombers. The American TROJAN (December 1948) envisioned 133 bombs (although only 50 existed) hitting 70 cities. A committee led by General Hubert R. Harmon reported in May 1949 that even if all precisely hit their targets, the USSR would not surrender, its leadership would not be seriously weakened, and its military could still operate in Western Europe, the Middle East, and Asia. The attacks would reduce Soviet industrial capacity by 30 to 40%, but only temporarily without follow-up attacks. The Harmon report had three immediate results: 1) It supported those within the United States Navy and elsewhere who criticized the centrality of atomic bombs and mass attacks on cities in American war planning. 2) It led to a substantial rise in nuclear-weapons production. 3) It caused the Joint Chiefs of Staff to, in fall 1949, assign SAC with the duty of slowing a Soviet invasion of Western Europe as part of NATO. Erroneous US and British intelligence reports led to exaggerated NATO estimates of Soviet conventional forces. One 1951 estimate foresaw 175 combat divisions allegedly prepared to simultaneously attack Western Europe, the United Kingdom, the Balkans, the Middle East, and North America. The perceived imbalance in forces was so great that American planners feared that even Britain would have to be abandoned during the invasion, a possibility they did not discuss with their British counterparts.