LEO I computer becomes operational

5th September 1951
LEO I computer becomes operational

In October 1947, the directors of J. Lyons & Company, a British catering company famous for its teashops but with strong interests in new office management techniques, decided to take an active role in promoting the commercial development of computers.

On 5 September 1951 the LEO I computer became operational and ran the world's first regular routine office computer job. This program was Bakery Valuations, which calculated the costs of ingredients for bakery products.

The company LEO Computers Ltd was formed in 1954.

Guinness World Records have accepted the evidence provided by Frank Land that LEO I was the first ever business computer - and they have a certificate to prove it! An engraved stone plaque and information board to remember LEO is also situated in Lyon's Walk near the site of Cadby Hall, Hammersmith in London. Cadby Hall was the location of Lyons' head office.

LEO II computers were installed in many British offices, including Ford Motor Company, British Oxygen Company, and the 'clerical factory' of the Ministry of Pensions at Newcastle. LEO III computers were installed in Customs & Excise, Inland Revenue, The Post Office and in Australia, South Africa and Czechoslovakia.

LEO Computers Ltd merged with the computer interests of English Electric in 1963 to form English Electric LEO, and later, English Electric Leo Marconi (EELM). Subsequent mergers eventually found LEO incorporated into ICL in 1968, whilst the Bureau operation, based at Hartree House, combined with Barclays to form Baric.

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