Initially restricted to members of the British Commonwealth, the Colombo Plan expanded rapidly to include non-Commonwealth nations such as Indonesia, Thailand, Vietnam, and the Philippines (later extended to the South Pacific) and to donors such as the United States and Japan. Japan's membership in 1954 illustrated briefly held American hopes that the Colombo Plan might become a vehicle for more than bilateral aid projects, in the same way that the Marshall Plan had been in Europe. Washington hoped that Japan's membership would facilitate rapid integration of developing Asian economies with Japan's economy—that is, raw materials flowing into Japan and capital flowing out to developing nations. In the mid-1950s, however, memories of World War II were still vivid, and there was little Cold War consensus among new Asian nations. Thus, Japan's role in the plan remained a minor one.
The Colombo Plan began with two separate operations. One operation was an economic development scheme inviting financial support for developmental projects such as dam and road building. The other operation was technical assistance—the promotion of technical expertise, education, and training in a broad range of activities that logically assisted economic development and sound administration. Separate groups—a Consultative Committee in the case of economic development and a Council for Technical Cooperation for other aid—comprising members of the Colombo Plan met regularly to examine requests for aid and coordinate responses. The development projects were the more expensive, and in the late 1950s and 1960s they included ambitious dam building, agricultural innovations, and other modernizing features. The Canadians built a nuclear power reactor in India, but an even more ambitious plan for a reactor and school in nuclear technology, servicing Southeast Asia and based in Singapore, was not realized.
The Colombo Plan continues today (with twenty-five member countries), but since the 1980s it has become a much-reduced concept, focused on security, drug advisory programs, and the like. It is hard to evaluate its impact up to the 1980s. Most of the more ambitious development schemes depended on U.S. aid that had little to do with the Colombo Plan. In fact, much of the American money labeled as Colombo Plan aid was only loosely associated with it. Some projects made significant differences but, on their own, could hardly be credited with transforming Asian economies. For other donor countries, such as Australia and New Zealand, scholarships granted under the technical assistance side of the plan provided Asian students with study opportunities at a tertiary level and helped foster dialogue while eroding anti-Asian sentiments at home.
Oakman, Daniel. Facing Asia: A History of the Colombo Plan. Canberra, Australia: Pandanus, 2004.; Tarling, Nicholas. Britain, Southeast Asia and the Onset of the Cold War, 1945–1950. Cambridge and New York: Cambridge University Press, 1998.