Fuchs’s information undoubtedly enabled the Soviet Union to build the atomic bomb more quickly than it could otherwise have done. Fuchs himself thought that he had saved the Soviet Union several years – though he added, on reflection, that he had speeded up the Soviet bomb “by one year at least.”126 But Fuchs, who had never been in the Soviet Union, knew almost nothing about the state of Soviet physics. The best-qualified estimates of the time that intelligence saved the Soviet Union have fallen into the range of one to two years.
