LEO was developed from the Cambridge EDSAC between 1949 and 1951 and ran the first commercial data processing job in the world, the bakery valuation in November 1951. The LEO was developed by John Pinkerton and his team at Cadby Hall, Hammersmith, London which was Joseph Lyons and Company’s main offices and manufacturing facilities. Pinkerton didn’t just copy EDSAC but he re-engineered it substantially to improve reliability and maintainability, vital for commercial computing, and to provide buffers on slow peripherals like paper tape, card readers and printers so that the peripherals could be run at full speed and be overlapped with processing.
The LEO Computer Society will be creating a series of events during 2026 to celebrate the event and to inform the public of the remarkable British Innovations during the 1950s which will be announced here, on Social media and in in the Press