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URGENT REQUEST: Do you have any LEO memorabilia - e.g. pieces of hardware, engineering drawings, charts and plans, programming information, computer files, correspondence or reminiscences?
If so, you can help us. We are collecting such material to join a growing archive at the Centre for Computing History in Cambridge, our partners in a National Lottery Heritage funded project to preserve, protect and promote the history of the world's first business computer.
Please contact for further details.

This is the site of the LEO Computers Society celebrating the World's first business computer.    
The LEO Computers Society aims to increase public knowledge and understanding of the early days of business computing - the basis for the transformation we all now take for granted. The Society also acts as a focal point for those who worked on LEO computers and encourages two-way communication - gathering reminiscences for our archive and giving opportunities to meet.
As part of our change to a Charitable Incorporated Organisation, we have updated the Society Constitution

It is not sufficiently widely appreciated that it was a British catering firm, J. Lyons and Co - famous for their teashops, Swiss rolls and ice cream and with a prescient interest in new office management techniques- which pioneered the development of computing for commercial applications.
As the Guinness Book of Records ratifies - Lyons Electronic Office (LEO) was the first business computer in the world.
In 1951 the LEO I computer was operational and ran
the world's first regular routine office computer job.
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The LEO Computers Society's mission is to ensure that the heritage of LEO is preserved, protected and promoted.

The importance of LEO has been recognised by displays in many prestigious institutions such as the Science Museum, London, the National Museum of Computing at Bletchley Park, the Centre for Computing History, Cambridge and as far away as Mountain View, California. There are LEO historic materials held in several universities and archives including those at Manchester, Warwick, Melbourne University and the Charles Babbage Institute, USA. Oral histories of LEO pioneers and practitioners are available to listen to on websites such as that of The British Library. We support a doctoral student at Middlesex University and we promote public lectures on LEO. Details of how you can find out more about LEO can be found in our complete directory of sources - LEOPEDIA - available on this website, see below.

The Society has long been determined to ensure that LEO material held by private individuals should be gathered together and made available for a wider audience. We are delighted to have recently formed a partnership with the Centre for Computing History, Cambridge. Together we applied for and were successful in gaining Heritage Lottery funding. Our project will collect LEO material, archive and digitise it where appropriate. We aim to establish a single window on to all the LEO collections wherever they are. We are also planning exciting new ways to tell the LEO story - for example, by creating a virtual reality (VR) version of LEO I.

We invite all our members and indeed anyone interested in ensuring that the LEO heritage lives on, to get involved in this project.

    Membership of the Society is open to:
  • all ex-employees of LEO Computers and its succeeding companies;
  • anyone who worked with a LEO computer;
  • and anyone who has a specific interest in the history of LEO Computers.
We encourage those who have an interest in LEO to join the Society- please see the Application Form. Membership is currently free of charge.
A comprehensive collection of references and holdings related to the story of LEO has been compiled by Frank Land, FBCS.   Now known as the LEOPEDIA and currently at 84 pages, it is regularly augmented. The areas covered are shown below in a clip from the Contents page of the LEOPEDIA.
The latest PDF version (13/06/2019) is available here......and an HTML version available here...