Sugar

Sugar was a natural sweetener found on the planet Earth. It was frequently added to drinks like coffee and tea, and was the basis for many deserts, such as chocolate cake. In February 1918, the United Kingdom began rationing sugar in response to the pressures of World War I. (EDA: Casualties of War) In 1963, the Doctor chatted with John about how tea with sugar was different from tea without sugar. (DW: Remembrance of the Daleks) In the 1970s, the Third Doctor stopped the Multi-Mobile by putting sugar cubes in its petrol tank. (TVC: The Multi-Mobile) The Cybermen poisoned the sugar in the Gravitron's employees' coffee in 2070. (DW: The Moonbase)