Welcome to the LEO Computers Society Website


  • LEO Matters issue 15, June 2024 - LEO Matters Issue 15, November 2024 has been published and circulated to Members and others. It can be downloaded by following the download link on this page .
  • Rebuild of EDSAC at TNMoC: Presented by Andrew Herbert - Andrew Herbert, is a distinguished Computer Science practitioner who hails from the Cambridge Tradition. Having held a very senior position in Microsoft Research, in retirement he is the leader of the project on display at TNMoC to construct a replica of the pioneering EDSAC I computer at the University of Cambridge which first went into […]
  • LEO on the Radio - Over time there have been a number of programmes on the BBC Radio which have talked about LEO. Neville Lyons put together material extracted from the BBC programmes together with relevant Slides to provide visual content and this was presented on 12 December 2023. A recording is available here Zoom Recording To listen to the […]
  • More on the UK IT Industry Award 2023 - BCS has published an article Online here
  • UK IT Industry Award 2023 - The LEO Computers Society and the Centre for Computing History have been awarded “Highly Commended” in the UK IT Industry awards for 2023., charities sector. John Paschoud, Vince Bodsworth, Peter Byford and Bernard Behr attended the Black tie event on November 8th at the Evolution Centre in Battersea Park
  • LEO Matters issue 14, November 2023 - LEO Matters Issue 14, November 2023 has been published and circulated to Members and others. It can be downloaded by following the download link on this page .
  • LEO Computers Society and CCH win Runner up position in BCS IT Innovation Award (Charities Sector) - The British Computer Society (BCS) and Computing ran their Annual IT Innovation awards event at the Evolution Centre in Battersea Park on Wednesday 8th Nov evening. One prize was for IT Innovation in the Charities Sector and this was won by Plant Heritage with LEO Computers Society and The Centre for Computing History (CCH) as […]
  • u3a Podcast on J. Lyons and the LEO 1 Story - Neville Lyons continues his contribution to the u3a Podcast series with an outline of the J. Lyons investment and development of LEO 1. https://www.leo-computers.org.uk/wp-content/uploads/2023/09/IMG_1491.jpeg
  • u3a Podcast on J. Lyons & Co. Story - Neville Lyons has participated in recent u3a radio podcast which covers J ​Lyons story, available on YouTube. J Lyons & Co was famous throughout most of the 20th century for its Teashops, Corner House Restaurants and food manufacture. Since 2008, Neville Lyons ((relative of co-founder) has given more than 200 presentations covering the history of J Lyons, the development and manufacture of […]
  • Virtual LEO I now available on iPad - The Virtual LEO I model is now available to download to iPad and is available from the Apple App Store More news on the availability of Virtual LEO 1 on Android devices can be seen on the new Website https://www.leo1.co.uk

The Centre for Computing History, Cambridge is our partner in a National Lottery Heritage funded project Swiss Rolls, Tea and the Electronic Office. To find out more about this click (Welcome to LEO)
There is also a regular Project Blog at (Project Blog).
During the Covid Pandemic the Museum has had to close its doors. As it  depends on school and individual visits for almost all its income, it has been appealing for donations. We hope that members may be able to help them in these difficult times. (See Here)



It was, surprisingly, a British catering firm, J. Lyons and Co – famous for their teashops, Swiss rolls and ice cream which pioneered the development of computing for commercial applications. As Guinness World 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.

The LEO Computers Society (which has charitable status) started life as a reunion society for people who worked on these remarkable machines. Its principal mission now is to ensure that LEO’s heritage is preserved, protected and – importantly – promoted to wider audiences. Read more about the LEO Computer Societies mission (Our Mission). If you want to understand the development timeline and the rationale for its development see what the Science Museum has to say.
More About Us

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 the Secretary@leo-computers.org.uk for further details.


Become a member

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 indeed anyone who has an interest in the history of LEO Computers.
  • we especially would encourage educators to join

We welcome the active participation of members – whether through volunteering as interviewers for oral histories, writing their own reminiscences, contributing to the newsletter or simply through spreading the word!

So Join Today

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