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the first business computer London,

View of a computer terminal that fills a whole room. On the terminal are buttons and dials and a plaque reading ‘LEO’.
Leo I electronic computer, c. 1960s. Science Museum/ Science & Society Picture Library

The LEO I (Lyons Electronic Office I) was the first computer used for commercial business applications.

J Lyons & Company ran teashops across Britain that were well known for their waitresses, affectionately nicknamed ‘nippies’. But the company was also interested in improving the way its work was managed and conducted, so it decided to build a computer that could support the collection and analysis of this information.

Working with the team at the University of Cambridge that had built the EDSAC computer in 1949, Lyons developed the LEO I, assembling it at the Lyons main factory building in Hammersmith, West London. The computer ran its first program on 5 September 1951, valuing the cost of goods that came out of the bakeries.

The company LEO Computers Ltd was formed in 1954 and went on to build LEO II and LEO III. These were installed in many British offices including those of Ford, Customs and Excise, the Inland Revenue and the Post Office. The later models were exported as far as Australia and South Africa.

Science Museum

Computing, Engineering,
Hammersmith, West London
Key Individuals
J Lyons and Co,