At the start of the Second World War in 1939, the United Kingdom was importing 20 million long tons of food per year, including about 70% of its cheese and sugar, almost 80% of fruit and about 70% of cereals and fats. The UK also imported more than half of its meat and relied on imported feed to support its domestic meat production. The civilian population of the country was about 50 million. It was one of the principal strategies of the Germans in the Battle of the Atlantic to attack shipping bound for Britain, restricting British industry and potentially starving the nation into submission.