British Tabulating Machine Company
The firm that sold Hollerith machines under licence across the British Empire, built the bombes for Bletchley Park, and eventually turned into ICL.
Founded in 1902 to sell Hollerith's machines in Britain and the Commonwealth, on royalty to the Americans. The designs therefore came from abroad, and the agreement bound the company tightly: limited freedom to develop machines of its own and an absolute bar on selling outside its territory. The tie to IBM was cut only in 1949, when the agreement lapsed and the firm became its own designer for the first time.
During the war its Letchworth works built some two hundred bombes for Bletchley Park. Chief engineer Harold "Doc" Keen turned the logic of Turing and Welchman into mechanics that stood up to round-the-clock operation by staff who were not told what the machine did. None of it could be boasted about afterwards either — the whole effort stayed secret into the 1970s, which cost the company the only track record it had as a genuine computer builder.
In 1959 BTM merged with its arch-rival Powers-Samas to form International Computers and Tabulators, absorbed into ICL in 1968. With that, the British punched-card industry ended as a single company: the country's last attempt at keeping a computer industry of its own.