British Tabulating Machine Company

The British Tabulating Machine Company (BTM) was a firm which manufactured and sold Hollerith unit record equipment and other data-processing equipment. During World War II, BTM constructed a number of "bombes", machines used at Bletchley Park to break the German Enigma machine ciphers. The company was formed in 1902 as The Tabulator Limited, after Robert Porter obtained the rights to sell Herman Hollerith's patented machines from the US Tabulating Machine Company (later to become IBM). By 1909, the company had been renamed the "British Tabulating Machine Company Limited".