Formed in 1959 with the merger of the British Tabulating Machine Co (BTM) and Powers-Samas Accounting Machines.

The company had works at Letchworth, Croydon, Castlereagh, Dartford, Stevenage, Alderley Edge, Chertsey, Cirencester, Kirkby, Southport and Stockport. In 1963, the company bought the the business-computer division of Ferranti.

In 1968, ICT merged with English Electric Computers to form International Computers Ltd (ICL).