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 runner up (Highly Commended) for the Virtual LEO I. The event was attended by Peter Byford, Bernard Behr, John Paschoud and Vince Bodsworth of the LEO Computers Society and more will be in the upcoming Newsletter as a Stop Press. Announcement
Read all about Virtual LEO I here

See the CCH Website Here

Below From right to left Bernard Behr, Peter Byford, Vince Bodsworth and John Paschoud attending the Award Event

LEO Computers Society and CCH win Runner up position in BCS IT Innovation Award (Charities Sector) Read More »

LEO Remembered has been substantially revised and added to by Hilary Caminer, of the LEO Computers Society and Lisa McGerty of the Cambridge Centre for Computing History. There was an event on 28th September on Zoom to launch the new book . You can also order copies of the book at the link below at GBP8 plus postage. Please specify quantity and address (especially country) for delivery if you want to order and we will send a cost quotation and instructions for payment.

Order your copies here .

A recording of the launch event can be viewed here

Launch of the massively revised LEO Remembered on 28 September Read More »

The LEO Computers Society and partners Centre for Computing History are delighted to announce that their film about LEO, the world’s first business computer has won the Association of British Science Writers (ABSW) Video of the Year Award 2022. 

LEO, otherwise known as the Lyons Electronic Office, was a pioneering British computer developed in the early 1950s by J. Lyons & Co., famous for tea, cakes and the teashops that were once part of the fabric of British life. 

The film was commissioned as part of a lottery-funded project ‘Swiss Rolls, Tea & the Electronic Office’, which is preserving, cataloguing and making accessible the heritage of this remarkable machine so as to raise awareness of this relatively unknown British story. 

Judges commented that the film was “an absorbing and textured piece with excellent and evocative archive footage”. It aims to introduce a whole new generation, from secondary school age upwards, to the remarkable story of the birth of a technology that, today, we take for granted.

Lisa McGerty, manager of the project said: “We’re honoured to have had the LEO film we commissioned – and which was expertly made by Richard Hollingham and Jamie Partridge of Boffin Media – recognised as the Association of British Science Writers’ Video of the Year. LEO’s story really is remarkable and it is a privilege for us to work with some of the surviving pioneers on this project, as well established film producers like Boffin. The first LEO computer was an astounding feat not just of engineering but also of vision by a company that had the foresight to recognise just how computers could revolutionise business at a time when computers didn’t really exist. Everyone should know about it.”

The film is freely available to watch at It will be signposted to schools and colleges as part of The Centre for Computing History’s learning programme.

1. The film has been created by Boffin Media, an award-winning production company specialising in science and space. The Producer is Richard Hollingham and the Director is Jamie Partridge.

2. The LEO Computers Society is committed to promoting and protecting LEO’s history. 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 with a specific interest in the history of LEO Computers. Among its members are pioneers from the very early days of computing and membership is currently free of charge. Visit Follow @leocomputers51.

3. Established in 2006, the Centre for Computing History is a charitable heritage organisation with a strong focus on learning. Since opening in Cambridge in August 2013, the Centre has helped people understand how tech has shaped the modern world and revolutionised the way we live, work and play through interactive displays and exhibitions, our schools programme, learning events and workshops, and an astonishing collection of computers old and new. Visit Follow @computermuseum 

4. Using money raised by the National Lottery, The National Lottery Heritage Fund inspires, leads and resources the UK’s heritage to create positive and lasting change for people and communities, now and in the future. Since The National Lottery began in 1994, National Lottery players have raised over £43 billion for projects and more than 635,000 grants have been awarded across the UK. Follow @HeritageFundUK on Twitter, Facebook and Instagram and use #NationalLotteryHeritageFund

 For further information on the museum, the Society, the LEO project or for images, please contact: Lisa McGerty (, 01223 214446 / 07825 794791) or Peter Byford (, 07944 038489).

We won Video of the year Read More »

Jason Fitzpatrick the CEO of the CCH gave LEO Computer Society members a virtual tour of the exhibits at the Museum on 27th April. The meeting was held on Zoom and recorded for those who wanted to attend but who were not able.

The recording is now available on this Website and can be viewed by following the link above. In addition an updated version of LEOPEDIA as at 30th April has been also uploaded to the Website

The Zoom Video can be viewed by following This Link and the updated LEOPEDIA Here

Zoom Recording of a tour of the Centre for Computing History now available Read More »

There was another Zoom on Monday 24 January 2022 at 15:30 GMT.
The topic was “Inside the LEO archive” and was led by Luke Thorne, our Archivist at the Centre for Computing History at Cambridge. A recording is available at


REUNION and LEO Exhibition: Sunday, 10th April 2022

From midday at the Victory Services Club, Marble Arch, London W2 2HF. As usual this will be an opportunity to meet old friends and colleagues and others with an interest in early computing. There will be refreshments and exhibitions of LEO related materials – as well as the usual raffle! Details to follow in the new year.

Tickets (to include a light lunch) cost £27 if bought before 31st January 2022 (£30 thereafter.)

To download a form to send with your application and with payment details click here

If you have any queries about this event or wish to book tickets, please email

Dates for your diary. Events for 2022. Follow this link for further information Read More »

September 1951  – At J. Lyons & Co on Wednesday, 5th September 1951 the Bakery Valuations programme was run to completion on real data as an experiment to test the hardware.  As noted in Ernest Lenaerts notebook for that date it ran from 3:50 to 5:35 without a fault and was the longest run of any programme at that time.


The BBC programme Antiques Road Trip made a stop off at Cambridge to visit the Cambridge Computer History Museum and interviewed Jason Fitzpatrick the Museum founder. Jason covered many interesting topics including early calculators, EDSAC, LEO and the BBC Micro and ARM chips.

You can hear and view the section from Cambridge Here

Antiques Road Trip Read More »

2021 marks LEO’s 70th Anniversary Year – unfortunately the Trustees felt they had to postpone the Reunion from 2021 but replace it with a series of Zoom events to celebrate the events of 1951 (see the post on the new Zoom dates) The new date for the Reunion at the Victory Services Club is Sunday, 10th April 2022

See Here for the new Zoom dates

70th Anniversary Read More »

On 15th February 1951, a LEO diary note read: ‘It can be said that on this day, LEO performed its first programme before HRH Princess Elizabeth.’

On this day 15th of February 1951 Princess Elizabeth visited Cadby hall and was give a demonstration of the Lyons Electronic Office

LEO I was still under development at that time but later in 1951 LEO ran its first programme.

The Society Secretary wrote to the Queen earlier and received this reply a few days ago.

Ernest Lenaerts who was one of the designers of LEO I kept a detailed diary with technical notes and recordings of events left the following entry in his record of 16 February 1951
HRH was no more and no less impressed than I had expected. The information printed by the Teleprinter was unintelligible except of course for the message printed at the bottom which provided some light relief. Fortunately LEO made few mistakes – obviously not subject to stage fright and the Demo went off smoothly. A little more interest was shown I think in the interior of the machine when she saw the complexity of the circuits – how many of this machines like these in existence?
Only one other in working condition – No others on commercial clerical problems. This auspicious occasion called for an enormous improve in general tidyness of the lab and I must make an effort to preserve this. My own desk was clear for the occasion – the first time in months. Work on the machine can go ahead again and I have been given a more or less free hand to proceed on which problem I deem the best tackled first. The object will be to bring the machine  to full operating condition as soon as possible so that Caminer & Co can get [[weaving]] on some of the programmes that they have kept up their sleeves for so long. The first and most obvious fault to be cleared is the corruption in the Teleprinter which I Think are due to breakthro in the output Unit. Other troubles to be cleared are occasional “1”s being added into the store. These have the effect of spoiling all of the test programmes received from Cambridge ” 

Princess Elizabeth’s visit to Cadby Hall on 15 February 1951 Read More »

Zoom Recordings Read More »

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 service in 1949.

On 26 April 2024 Andre spoke to the LEO Computer Society on Zoom  about the reconstruction project , now close to completion.  He spoke of the challenges of reconstructing a machine for which there were very few surviving circuit diagrams – the EDSAC reconstruction team worked mostly from contemporary photographs and secondary sources and research into established circuits for “computing with waveforms” known to 1940s electronics engineers.

A recording is available here Zoom Recording

Copy of the slides used can be found here Slides



Rebuild of EDSAC at TNMoC: Presented by Andrew Herbert Read More »

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 original BBC material without the slides you can follow the links below.

LEO the Electronic Office from BBC Radio 4 Computing Britain

LEO BBC Radio 4 Extra

LEO Making History BBC Radio 5 Live Outriders

LEO on the Radio Read More »

December 23

Since 2018 the Cambridge-based Centre for Computing History (CCH) has been working in partnership with the LEO Computers Society on a lottery-funded project to provide a long-term, centralised home for the society’s historically important and internationally significant heritage relating to LEO (Lyons Electronic Office), the world’s first business computer, so that the collection is accessible to the public.

The lottery project ended formally in June this year, but the cooperation of the two organisations continues. The result to date is that the Cambridge centre now looks after many thousands of individual items – as well as their newly created digital equivalents – and the partners continue to promote the LEO story in various ways. Their most innovative approach is an award-winning digital ‘rebuild’ of the original LEO, available both in a display at CCH and, in a major step forward in opening up access from anywhere in the world, via tablet devices.

The virtual LEO is an historically accurate digital representation of the first LEO machine. Unlike a physical rebuild, it also points to the social context of post-war London and the Lyons company context within which LEO I was constructed.

And because the staff of J Lyons & Company and LEO Computers Limited were meticulous record keepers, recording not just decisions at every step of the journey, but the reasons for those decisions and their consequences, the museum has been able to cast the collection in a wider social context, bringing the human and social stories involved to the fore.

The virtual LEO app is already picking up industry awards, most recently last month when it achieved a ‘highly commended’ in the charities category of the British Computer Society’s UK IT awards, a glitzy affair held annually to reward achievements across the IT industry.

For further details on what the app is and how to download it, visit the LEO I website


Virtual LEO I

In May this year, a PC-based version of the virtual LEO was installed at the Centre  for Computing History and Dr Lisa McGerty, Chief Executive of the museum and the project’s lead commented, “Watching visitors of all kinds use it since then has been a real joy for me.  And now, the virtual LEO has also been made available for access from the ubiquitous Apple iPad and the new app is going down a storm.”

Using either version of the virtual LEO, it is possible to ‘wander around’ the LEO room in Cadby Hall, the former Lyons’ HQ complex in Hammersmith, and view the racks of valves, hear all the peripherals and even look out of the window at the 1950s smog. Within the app, there are 35 interactive objects that can be ‘picked up’ and explored, and there are 44 documents, six film snippets and many photos from the archive, accompanied by over 40,000 words of explanatory text divided into six themes. It has been purposely designed in layers so that it is perfectly possible just to walk around the room and see and hear what it was like to operate the first LEO, or one can dig deeper into the wider story.

An Android version of the app is also currently in development and is planned for release shortly.

In a further comment, Hilary Caminer, the LEO Society’s secretary expressed her own amazement in saying: “I think it is a remarkable feat to put that enormous, epoch-making and room-sized early mainframe on to a palm-sized tablet. What would those early pioneers have thought and said?”

Other highlights of the collection

Over the course of the project, there were more than 50 separate deposits of LEO material made to the Cambridge museum by LEO Society members, some consisting of a single document or photograph, but the majority were of multiple documents – in some cases boxes of them – and there were some objects too, such as small pieces of various LEO machines including tape reels and logic boards.

These have been catalogued, digitised and in some cases transcribed, making more than 1,600 separate items available online to all, via the CCH website. These incorporate almost 13,000 scanned pages of documentation in total. On the CCH website these sit alongside the CCH version of the LEO Society’s Leopedia database, extending that resource in a wholly searchable and search engine optimised way. Whereas Leopedia lists references to secondary sources of information on LEO in books, journals and in the media, the archive catalogue lists and makes available the primary material.

The digitised LEO collection and the CCH version of Leopedia can be found at

Finding aids are also available and are being extended all the time so that the collection can be searched easily by people who know nothing about LEO – for example by subject – see

The archive includes reports from visits Lyons staff made to Cambridge at the very beginning of the Lyons-Cambridge University partnership during the development of EDSAC; photographs of the construction of LEO I, particularly those that point to the experimental nature of the early machine; a memo from TR Thompson reporting on the first fully successful and complete run of the world’s first commercial computer job, Lyons Bakery Valuations, which was completed at 2:35pm on 30th November 1951; extremely rare BBC film footage of LEO I running the Lyons payroll as well as other snippets of film; over 60 oral history interviews and more than 200 written reminiscences collected during the project and over the years. And much more besides.

LEO Documentary Film

The lottery project funding also allowed for the creation of a short documentary of the LEO story. Produced by Boffin Media, the film won the Association for British Science Writers (ABSW) Video of the Year Award in July 2022.

The film is available on YouTube and can be found via the museum’s website ( It was produced to coincide with the 70th anniversary of LEO I’s first fully successful live program run in November 2021.

-ends –



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.

IT Industry awards 2023

John Paschoud, Vince Bodsworth, Peter Byford and Bernard Behr attended the Black tie event on November 8th at the Evolution Centre in Battersea Park

UK IT Industry Award 2023 Read More »

Neville Lyons continues his contribution to the u3a Radio Podcast series with an outline of the J. Lyons investment in and development of LEO 1.

u3a Radio Podcast, September 2023

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 LEO, the world’s first business computer and Art in the Lyons Teashops.

u3a Podcast on J. Lyons and the LEO 1 Story Read More »

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