Among the nationalised industries, the largest in terms of fixed capital investment were the electricity and the railway industries, which accounted for 8 per cent and 2.5 per cent respectively of gross domestic fixed capital investment in 1951. Of gross domestic fixed capital formation in plant and machinery, electricity accounted for 15.4 per cent, and as such was the largest single area of industrial investment in this category. Of gross domestic fixed capital formation in vehicles, ships, and aircraft, railways accounted for 12.8 per cent, less than the 23 per cent in shipping and 22 per cent in distribution and other services, but again the largest single industry investing in this category. Like most nationalised industries, these were capital intensive, especially electricity whose capital–labour ratio was extremely high. The plant choices made by managers in each industry were clearly important, affecting as they did the efficiency of the current use of scarce resources and the subsequent productivity of each industry. It was specifically on this issue of raising the quality of plant choice that some economists saw improvements being facilitated by nationalisation in monopoly form.

In a monopoly, it was argued, managers would be free of the supplyside uncertainties which arose in competitive markets from ignorance of the fixed capital investment intentions of competitors. Given such hopes, the subsequent academic criticism of the plant choices made in a number of nationalised industries in this period is striking.