Why does Britain encourage immigrants from 1950s to 1960s? I urgently need an answer! ! ! thank you

1945, Germany was defeated, and Britain began to prepare to restore its national strength. First, 1948 began to accept the first batch of West Indies, mainly using them as bus drivers. After World War II, in order to rebuild the establishment of Britain, the British government encouraged the acceptance of immigrants. In the 1950s, Indians and Pakistanis were mainly accepted, and they were mainly used for textile and engineering work. After 60, Australia, New Zealand and Canada will no longer be restricted from naturalization. All these policies are aimed at restoring Britain's economic development and urban infrastructure.

Because in World War II, Britain did not rely on the natural barrier of the English Channel to let the Germans enter the British territory, but the important cities of the whole country were bombed into ruins by German bombers. You know the power of German weapons at that time. . .