One of the basic concepts of British Socialism is the solidarity of the working class. Acceptance of this concept makes it difficult for the industrial worker to think of the Communist, who comes from the same town, speaks with the same accent, wears the same clothes, as an enemy. There is a pathetic ingenuousness about workers who try to tell the visitor that the Communists "are just the same sort of blokes as us except they've got a different political idea." The _Daily Mirror_ team in its portrayal of the trade unions devoted a chapter to "The Communist Challenge." Significantly, a large part of the chapter provided an incisive and illuminating illustration of just how the Communists move to gain control of a union. Where else are the Communists strong? They are in control in some areas of the National Union of Mineworkers. Arthur Horner, the Secretary of the Union, is a Communist. But they are being fought hard in the NUM by men like Sam Watson, who heads its Durham region. The connection in the Communist mind between the control of the NUM and the ETU is obvious. Control of these two unions would enable Communists to halt the flow of coal and electric power to Britain's factories. Not much more is needed to cripple a nation's economy. But the Communists press on. They establish cells in the aircraft industry. They work industriously at fomenting trouble on the docks, especially in the ports--such as London, Liverpool, and Glasgow--through which most of the exports pass. Already the threat to block coal and power can be augmented with a threat to halt defense production and exports. It is improbable that the Communists are now powerful enough to carry their program to a triumphant conclusion. But they are on their way. How do they work? Very much as they do elsewhere in Europe. In Britain, as in Germany or Italy or France, the Communists care very little about better pay or better working conditions for union members. Their objective is power, power that will enable them to push the interests of the Union of Soviet Socialist Republics. And, to repeat, they have learned that for them power in Britain is obtainable only through control of the unions and not through Parliament. The Communists try to establish cells in every important factory in Britain. These cells maintain contact with the district secretary of the Communist Party, who knows from the cell exactly what sort of work the factory is doing. Little wonder that Soviet visitors are incurious about the details of British production when they are shown British factories. The information obviously is safely filed in Moscow.