Britain did not have enough farmland to sustain its increased population. The problem was solved by importing a large number of goods from the British Empire.
The German Government tried to disrupt delivery of goods by sea to Britain. Many British merchant ships were destroyed by German U-boats.
In order to cope with reduced supplies, the Government introduced food rationing in 1940.
Rationing helped to change attitudes - the fact that everyone was restricted to buying a certain amount of goods, created a sense of sharing and cooperation in Britain.
It was accepted that the Government was more involved in people’s health and food intake.