International Computers Ltd (ICL) was the largest British computer manufacturer, operating from 1968 until 2002, when it was rebranded as Fujitsu Services Ltd. The relationship with Fujitsu began in the early 1980s as a technology partnership, with ICL gaining access to Fujitsu’s cutting edge ASIC technology which was used in the Series 39 mainframe range. Fujitsu became sole shareholder in 1998. The company was formed through a government driven succession of mergers of companies including International Computers and Tabulators (ICT), English Electric, Elliott Automation, LEO and Marconi. ICT was itself formed from the British Tabulating Machine Company (BTM) and Powers-Samas. During the Second World War, BTM developed the Bombe machine used to crack the German Enigma code.
The company manufactured a huge variety of different systems ranging from small personal computers, such as the One Per Desk, minicomputers such as System 25 and DRS6000, small mainframes such as ME29 and 2903, and several ranges of large mainframe systems – System 4, 1900, 2900, Series 39 and Trimetra.
The company also developed an extensive range of system and application software. Major operating systems included George 1/2/3 (for 1900 systems), TME (for ME29) and VME (for 2900 and Series 39).