Where Britain in 1940 got its food from
An instructive combining of cartography, seaborne trade and wartime economics, this map, circa 1940 (no sadly I don’t have the source yet) explains it all rather well.
The text in the box, lower left corner, says: “Much of Britain’s food must be imported. Some essential foods are rationed, others such as bread are not. In every kitchen there are ways of making these foods go further. Remember that little economies are multiplied by every home in the land. In this way British housewives can lighten the heavy load of our Merchant Navy.”