Leopedia is the LEO Computers Society’s guide to references and holdings related to the story of LEO.

Here at the museum we've taken the opportunity to locate the LEO collection we look after within this wonderful resource, so that future researchers and the public can access as much LEO content as possible from one central place. Leopedia can be accessed below.

This resource is maintained by Professor Frank Land OBE, with support from CCH as part of our HLF-funded partnership project 'Swiss Rolls, Tea & The Electronic Office: A History of LEO, the World's First Business Computer'. If any reader knows of any other reference please let Frank Land know at f.land@lse.ac.uk.

The folders in the top half of the page relate mostly to references to and holdings of LEO material in places other than at the Centre for Computing History and in many cases entries are simply signposts to where the material can be found.

The folders underneath relate to the LEO Computers material we hold here, subdivided into the archives of some of the prominent people in the LEO story, details of whom are below.

You can also view the archive catalogue of the LEO collections held here at the museum:

CMLEO/DC - David Caminer Papers
CMLEO/EL - Ernest Lenaerts Collection
CMLEO/FL - Frank Land Collection
CMLEO/PB - Peter Bird Collection
CMLEO/LS - LEO Computers Society Collection
CCH LEO Artefacts Collection


David Tresman Caminer joined Lyons as a management trainee before the Second World War and was responsible for the deployment of LEO in the Lyons business. Most of his papers have been donated by David's daughter Hilary and form a major part of the archive. The LEO-related papers are mostly digitised. Caminer's most prominent achievement however, in 1980, was implementing the computer and communications infrastructure for the European Economic Community (precursor to the European Union (EU)) in Luxembourg. This work was recognised with his appointment as OBE for services to the computer industry. Caminer's papers from this time are also lodged at the Centre for Computing History, although only a small amount has been digitised as part of the LEO project.

Ernest Lenaerts started work for J. Lyons & Co. in the late 1920s doing clerical work, but later became a principal engineer on LEO I, having trained as a wireless mechanic during the war. In late 1947, Lyons seconded him to Cambridge both to learn about emerging computer technology and to help in the design of EDSAC. When Lyons commenced building LEO I he joined John Pinkerton in the design team. The notebooks he kept during his engineering work on LEO I are believed to be the only surviving contemporary written account of the installation and development of the computer at Cadby Hall in the early 1950s and they are amongst the most historically important papers in the archive.

Frank Land today is the LEO Computers Society's historian, with responsibility both for Leopedia and for the Society's oral history interview programme, amongst other things. In 1952, he had joined Lyons as a programmer on LEO I, going on to lead LEO Computers' sales and systems consultancy team, which he did for 15 years before joining the London School of Economics in 1967 to establish the UK’s first university programme in information systems. 

Peter Bird, historian of Lyons and LEO, gathered a collection of documents, photographs and other material in preparation for his pioneering book LEO - The First Business Computer (1994). These then passed to the LEO Computers Society, and have been loaned to the Centre for Computing History for digitisation and cataloguing as part of the project. His papers are many and varied and most have been digitised.

The remainder of the LEO archive consists of miscellaneous materials relating to the history of the LEO computer collected by the committee and members of the LEO Computers Society and loaned to the museum for inclusion in the archive. Much of this material has been digitised.

At the Centre for Computing History we also have a small LEO collection of our own, mostly consisting of physical artefacts and these are also presented here for ease.

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