J. Lyons and Co., one of the UK's leading catering and food manufacturing companies in the first half of the 20th century, sent two of its senior managers, Oliver Standingford and Raymond Thompson, to the USA in 1947 to look at new business methods developed during the Second World War. During their visit they met Herman Goldstine, one of the original developers of ENIAC, the first general-purpose electronic computer (though it had no stored program). Standingford and Thompson saw the potential of computers to help solve the problem of administering a major business enterprise. They also learned from Goldstine that, back in the UK, Douglas Hartree and Maurice Wilkes were actually building another such machine, the pioneering EDSAC computer, at the University of Cambridge.

On their return to the UK, Standingford and Thompson visited Hartree and Wilkes in Cambridge, and were favourably impressed with their technical expertise and vision. Hartree and Wilkes estimated that EDSAC was twelve to eighteen months from completion, but said that this timeline could be shortened if additional funding were available. Standingford and Thompson wrote a report to the Lyons' Board recommending that Lyons should acquire or build a computer to meet their business needs. The board agreed that, as a first step, Lyons would provide Hartree and Wilkes with £3,000 funding for the EDSAC project, and would also provide them with the services of a Lyons electrical engineer, Ernest Lenaerts. EDSAC was completed and ran its first program in May 1949.

Following the successful completion of EDSAC, the Lyons' board agreed to start the construction of their own machine, expanding on the EDSAC design. The Lyons machine was christened Lyons Electronic Office, or LEO. On the recommendation of Wilkes, Lyons recruited John Pinkerton, a radar engineer and research student at Cambridge, as team leader for the project. Lenaerts returned to Lyons to work on the project, and Wilkes provided training for Lyons' engineer Derek Hemy, who would be responsible for writing LEO's programs. The first business application to be run on LEO was Bakery Valuations. This was initially run as a test program on 5 September 1951, and LEO took over Bakery Valuations calculations completely on 29 November 1951.

LEO I's clock speed was 500 kHz, with most instructions taking about 1.5 ms to execute. To be useful for business applications the computer had to be able to handle a number of data streams, input and output, simultaneously and its chief designer, Dr. John Pinkerton, therefore designed the machine to have multiple input/output buffers. In the first instance these were linked to fast paper tape readers and punches, fast punched card readers and punches, and a 100 line a minute tabulator. Later other devices including magnetic tape were added. Its ultrasonic delay line memory based on tanks of mercury, with 2K (2048) 35-bit words (i.e., 8¾ K bytes), was four times as large as that of EDSAC. The systems analysis was carried out by David Caminer.

Lyons used LEO I initially for valuation jobs, but its role was extended to include payroll, inventory and so on. One of its early tasks was the elaboration of daily orders which were phoned in every afternoon by the shops and used to calculate the overnight production requirements, assembly instructions, delivery schedules, invoices, costings and management reports. This, arguably, was the first instance of an integrated management information system plus a computerised call centre. The LEO project was also a pioneer in outsourcing: in 1956 Lyons started doing the payroll calculations for Ford UK and others on the LEO I machine. The success of this led to the company dedicating one of its LEO II machines to bureau services. Later, the system was used for scientific computations as well. Met Office office staff used a LEO I before the Met Office bought its own computer, a Ferranti Mercury, in 1959.In 1954, with the decision to proceed with LEO II and interest from other commercial companies, Lyons formed LEO Computers Ltd. The first LEO III was completed in 1961. This was a solid-state machine with a ferrite core memory. It was micro-programmed and was controlled by a multi-tasking operating system. In 1963, LEO Computers Ltd was merged into English Electric Company and this led to the breaking up of the team that had inspired LEO computers. English Electric Company continued to build the LEO III, and went on to build the faster LEO 360 and even faster LEO 326 models, which had been designed by the LEO team before the takeover. All LEO IIIs allowed concurrent running of as many as 12 application programs through the Master program operating system. Some were still in commercial use with GPO Telephones, forerunner of British Telecom, until 1981, which remained usable through parts cannibalised from redundant LEOs purchased by the GPO.

Users of LEO computers programmed in two coding "languages": Intercode, a low-level assembler type language, and CLEO (acronym: Clear Language for Expressing Orders), the COBOL equivalent.

Many users fondly remember the LEO III and enthuse about some of its quirkier features, such as having a loudspeaker connected to the central processor which enabled operators to tell if a program was looping by the distinctive sound it made.

English Electric LEO Computers Ltd or English Electric Leo Marconi (EELM) eventually merged with International Computers and Tabulators (ICT) and others to become in 1968 International Computers Limited (ICL).

Notes

Books

• Bird, P.J. (1994). LEO: The First Business Computer. Wokingham: Hasler Publishing Co. ISBN 0-9521651-0-4.
• Campbell-Kelly, M., (1989). ICL: A Business and Technical History. Oxford: Clarendon Press.
• Caminer, D.T., Aris, J.B.B., Hermon, P.M.R., Land, F.F. (1996). User-Driven Innovation: The World’s First Business Computer. London: McGraw-Hill. ISBN 0-07-009501-9.
• Carmichael, H., editor (1996). An ICL Anthology, Chapter 6: LEO, Laidlaw Hicks, Surbiton, UK.
• Ferry, G. (2004). A Computer Called LEO: Lyons Tea Shops and the World's First Office Computer. Hammersmith: Harper Perennial. ISBN 1-84115-186-6.
• Hally, M. (2005). Electronic Brains: stories from the dawn of the computer age. Washington:Joseph Henry Press. Chapter 5: LEO the Lyons Computer. ISBN 0-309-09630-8.
• Land, F.F., (1997). LEO, the First Business Computer: A Personal Experience. In Glass, R.L., editor. In the Beginning: Recollections of Software Pioneers, pages 134—153. IEEE Computer Society, Los Alamitos, CA.
• PEP, (1957). Three Case Studies in Automation, PEP, London.
• Simmons, J.R.M., (1962). LEO and the Managers, MacDonald, London.

Articles

• Aris, J.B.B. (1996). "Systems Design ... Then and Now". Resurrection, Summer issue 1996.
• Land, F.F. (1996). "Systems Analysis for Business Applications". Resurrection, Summer issue 1996.
• Aris, J.B.B. (2000). "Inventing Systems Engineering". IEEE Annals of the History of Computing, Vol. 22, No. 3, July—September, pp. 4—15
• Land, F.F. (2000). "The First Business Computer: A Case Study in User-Driven Automation". IEEE Annals of the History of Computing, Vol. 22, No. 3, July—September, pp. 16—26.
• Caminer, D.T. (1958), "...And How to Avoid Them". The Computer Journal, Vol. 1, No. 1.
• Caminer, D.T. (1997). "LEO and its Applications: The Beginning of Business Computing". The Computer Journal, Vol. 40, No. 10.
• Caminer, D.T. (2003). "Behind the Curtain at LEO: A Personal Reminiscence". IEEE Annals of the History of Computing, Vol. 25, No. 2, April—June, pp3—13.
• Hendry, J. (1988). "The Teashop Computer Manufacturer: J. Lyons". Business History, Vol. 29, No. 8, pp. 73—102.
• Land, Frank (1999). "A Historical Analysis of Implementing IS at J. Lyons." In Currie, W.G.; Galliers, R.D., editors. Rethinking Management Information Systems, pp. 310—325. Oxford University Press.