In England, the term "biro" is used to refer to a ballpoint pen. The term "biro" comes from the name of the Hungarian newspaper editor Laszlo Biro, who invented the ballpoint pen in the 1930s. Biros invention successfully coupled ink-viscosity with a ball-socket mechanism which acted compatibly to prevent ink from drying inside the reservoir while allowing controlled flow. Biro filed for a British patent on June 15, 1938, and the pen was later licensed by the British engineer Frederick George Miles and manufactured by his company Miles Aircraft, to be used by Royal Air Force aircrew as the "Biro". The Bic Cristal, which is a type of ballpoint pen, is reportedly the most widely sold pen in the world and is often referred to as a "biro".