Bulletin of Computer Conservation Society, Issue 32, New Year. LeoComputers developed the Leo III as a medium size commercial computer, and included timesharing after several members of John Pinkerton’s development team attended the colloquium on the design for Orion timesharing presented by George Felton at the Cambridge Maths Lab. Timesharing was demonstrated on Leo III in January 1962, and on Orion in April 1962. The Leo systems were first delivered to customers in April 1962. Orion, having been delayed by hardware problems, was not delivered to a customer till March 1963. English Electric announced the KDF9 in 1960 as a small scientific computer, with timesharing as an optional extra [Ref: 2] involving additional hardware and a specific version of the ‘director’ software. That was done independently of the Orion and Leo developments. http://www.cs.man.ac.uk/CCS/res/res32.htm#e
