Only one LEO I computer ever existed, there were 10 LEO II computers and almost 40 standard LEO IIIs were installed around the UK and abroad.

The early LEO I programs were all known numerically within Lyons/LEO Computers. Each one was groundbreaking, in that computers at this point in time (the early 1950s) were not used for business processes. Click on the blue links or the blue arrows at the bottom of the page to see all the items that have been tagged for each program.

L1: Lyons Payroll. L1 initially referred to the payroll for Lyons bakeries staff but was later extended to all Lyons staff (over 20,000 people in 1955).

L2: Lyons Teashop Orders David Caminer developed the idea of standard orders for teashops that would be delivered as routine unless the manageress phoned to amend it. These revised orders were then handled by LEO I and the program then prepared and placed orders to the respective production departments within Lyons, prepared packing lists for despatch, cross-charged the various departments and provided stock control and management information for the business.

L3: Lyons Bakery Valuations The L3 job produced valuations of the output and sales of the Cadby Hall bakeries. As the first commercial computer program ever run, It is incredibly important in the history of computing. After much development work and many trials, the full program was finally completed for the first time on 30th November 1951 having having taken three days to run.

L4: Lyons Tea Blending The L4 job relates to the buying, blending and stock control of Lyons' teas.