Ferranti Ltd began working on computers in 1947, and by 1949 had established a Computer Group within the company. The Group worked with academic researchers, notably at the Universities of Manchester and Cambridge, and delivered the world's first commercially available computer in 1951: the Ferranti Mark 1. The collaboration with Manchester went on to produce the Ferranti Mercury and Atlas, whilst work with Cambridge led to the Atlas 2 or Titan. In 1953-1955 Ferranti set up a sales and development centre in central London, at Portland Place, in order to encourage a market for their products. A Pegasus computer was built on site. Other machines developed in the 1950s included the Pegasus II and Perseus models, as well as the Orion models. These machines were found to be useful in the aerospace industry and for nuclear research. From 1958-1962 Ferranti attempted to dramatically improve performance with a completely new design of computer: the Atlas. Background research was carried out at the University of Manchester and was known as the MUSE project. In 1963 the computer department was sold to International Computers and Tabulators. However, Ferranti continued to produce computers for the industrial sector through the Ferranti-Packard division, and work continued at the company's Bracknell, Wythenshawe and Cheadle Heath sites in industrial computing, automation and military computing. In the 1960s and 1970s the company developed its Argus models. Ferranti Computer Systems Ltd was formed in 1977 to bring together Ferranti’s computing divisions at Bracknell (digital systems), Wythenshawe (automation), and Cheadle Heath (military systems). The new company had a workforce of 4,400 and a £30 million pound annual turnover. The company was successful throughout the late 1970s and into the 1980s. Ferranti Computer Systems developed and manufactured control, monitoring and communication systems for industrial processes such as oil and gas extraction, public utilities, data communications networks and road transport. They were also involved in information systems including for air transport, providing data processing terminals, office systems, industrial and commercial local area networks. The company also supplied equipment to end users. As well as being active in the UK, by 1988 the company had subsidiaries in Australia, West Germany, Belgium and America. In 1994 Ferranti entered receivership. The computing division was sold to a division of Thomson-CSF, known as SYSECA. The company adopted the name Ferranti-SYSECA, which fell out of use around 1996. Ferranti Computer Systems merged with Thales UK in 2000, whereupon all operations were moved to Cheadle Heath on the outskirts of Manchester.

Ferranti International plc was an electrical engineering company originally established in 1883 as S Z de Ferranti. Sebastian Ziani de Ferranti had previously worked for Siemens Brothers in London before starting his first company, Ferranti, Thompson and Ince Ltd, in 1882 to manufacture alternators. When this company was wound up in 1883, de Ferranti bought back his patents in his alternator design and set up S Z de Ferranti with C P Sparks the same year. The business became a limited liability company in 1889, changing name to S Z de Ferranti Ltd. In 1896, the company moved from London to new premises in Hollinwood, Oldham, where land and labour were cheaper. In 1901, a new company name, Ferranti Ltd, was registered. Ferranti Ltd acquired the undertakings and assets of S Z de Ferranti Ltd the same year. The company ran into financial difficulties in 1903, largely through the investment in developing steam engines and dynamos. At the instigation of the debenture stockholders the company went into voluntary receivership. In 1905, the company was relaunched under a scheme of reconstruction, with production limited to the manufacture of switch gear, transformers and instruments. De Ferranti himself took a less active role in the running of the reconstituted company. Ferranti Ltd expanded its output in 1912 from electricity generating and distribution equipment to include electrical domestic appliances, establishing the Domestic Appliance Department. Expansion overseas began in 1913 when the Ferranti Electric Company of Canada was created as a separate business to the main company. By 1914, Ferranti Ltd was spread over several sites. It suspended normal production during the First World War and concentrated on the manufacture of shells. This was the first of Ferranti’s government defence contracts. The 1920s saw a resumption of manufacturing of civilian products. In 1923, production of audio frequency transformers signalled Ferranti Ltd’s move into electronics. In 1926, the company resumed manufacturing domestic appliances, beginning with electric fires, and began trading in the United States as Ferranti Electric Inc, New York. 1927 saw the re-establishment of the Domestic Appliance Department. In 1929, Ferranti Ltd began producing commercial radio receivers and in 1935 established its Moston radio factory, to which the Domestic Appliance Department moved in 1937. Shortly afterwards, television manufacturing started at the Moston site. Sebastian Ziani de Ferranti died in 1930, and his son Vincent de Ferranti became company chairman in his place. During the 1930s, the company became closely associated with devices that would feature strongly in the Second World War, including thermionic valves (vacuum tubes) used in radios and radar, avionics and naval instruments. During the Second World War, Ferranti Ltd produced marine radar equipment, gyro gun sights for fighters and one of the world’s first IFF (Identification Friend or Foe) radar systems, which reduced the possibility of firing on friendly aircraft or ships. In 1943, the company opened its Edinburgh factory to manufacture gyro gun sights. The Edinburgh site would become Ferranti Ltd’s hub for the manufacture of military defence equipment. Ferranti Ltd retained its interest in the defence sector after the Second World War. From 1948, the company began to develop guided missiles, especially the Bloodhound, at the Moston factory and later at the Wythenshawe factory. While the defence and communication market expanded throughout the 1950s, domestic products became unprofitable and were dropped. The company sold its radio and television interests to E K Cole Ltd in 1957, and the Domestic Appliance Department closed the following year. Ferranti became increasingly associated with ‘high-tech’ devices, including microwave communications equipment built at Poynton, near Stockport. Ferranti Ltd moved into computing in 1949, with the establishment of the Computer Department. The department produced the first Ferranti Mark I computer, a commercial version of the ‘Baby’ computer developed by Manchester University, at the Moston factory in 1951. It was the world’s first commercially produced computer. Computer production moved to a factory in West Gorton in 1956, but the Computer Division was sold to International Computers and Tabulators Ltd (ICT) in 1963. Other sections of the company continued to develop computer technology for more specialised applications. Ferranti Ltd also invested in semiconductor research, leading to its development of the first European microprocessor, the F-100L, at its Bracknell plant. Ferranti Ltd also produced non-standard silicon chips to suit individual customers’ needs. The Hollinwood factory continued to produce generating plant, such as large transformers, establishing the Distribution Transformer Department in 1957. This department operated until 1967. By 1975 the company was in financial difficulty and the British Government bought a 50% stake in Ferranti Ltd to enable the company to continue developing its telecommunications and computerised control systems. In 1984, the company was restructured into five operating divisions: Ferranti Defence Systems, Ferranti Industrial Electronics, Ferranti Computer Systems, Ferranti Electronics, and Ferranti Instrumentation. Ferranti Ltd merged with the US based International Signals and Control Group in 1987. The company traded very briefly as Ferranti plc in May 1988, prior to its official name change to Ferranti International Signal plc. The US company had been over-valued because of fraudulent practice. This affected the operation of the newly formed company, and the Defence and Guided Weapons Divisions were sold off to competitors in the area of defence work. Following the discovery of the fraud in 1989, Ferranti International Signal plc was renamed Ferranti International plc in 1990. The fraud amounted to a loss to Ferranti of £215 million as a result of this the company began legal proceedings against the former Chairman of International Signals & Control Mr James Guerin and three other senior employees. Ferranti were successful and Mr Guerin was ordered to pay $189.9 million to the Ferranti group. A similar judgement was given against the others who were also ordered to repay $189.9 million to the group. As a consequence of the fraud Ferranti had to dispose of several of its interests in order to raise badly needed cash to reduce its debt burden. Amongst the companies sold were Ferranti Defence Systems Group to the General Electric Company. The Italian companies owned by Ferranti International plc were sold to Finmeccancia plc. Various other smaller interests, including civil computer maintenance, Dundee components and laser business, and a joint venture Thomson-CSF SA were also sold. Not all the money was recovered, and on 1 December 1993 Ferranti International plc went into receivership, with the remaining company divisions sold off.