As with Diocletian's Edict on Maximum Prices, shortages lead to black markets where prices for the same good exceed those of an uncontrolled market. Furthermore, once controls are removed, prices will immediately increase, which can temporarily shock the economic system. Black markets flourish in most countries during wartime. States that are engaged in total war or other large-scale, extended wars often impose restrictions on home use of critical resources that are needed for the war effort, such as food, gasoline, rubber, metal, etc., typically through rationing. In most cases, a black market develops to supply rationed goods at exorbitant prices. The rationing and price controls enforced in many countries during World War II encouraged widespread black market activity. One source of black-market meat under wartime rationing was by farmers declaring fewer domestic animal births to the Ministry of Food than actually happened. Another in Britain was supplies from the US, intended only for use in US army bases on British land, but leaked into the local native British black market.