Dr John Robert Horton

After studying at Clifton College, Bristol, John read Mathematics (Exhibitioner) at St John's College, Cambridge. An Archimedean, he worked countless nights on the Cambridge Maths Lab's Titan computer. Following graduation, John completed a Diploma in Computer Science and then a PhD.

His research on Addressing and Protection in operating systems was based on the design of the Capability Machine with Professor Sir Maurice Wilkes providing guidance. John worked on EDSAC II, and was present at the closing down ceremony alongside Wilkes.

John joined GEC Computers as a software engineer, becoming instrumental in developing the GEC 4000 multi-access system, and later heading up the military systems division.

John then joined Acorn Computers as Technical Director. He moved to Net-tel ComputerSystems – of which he was a founder Director - in 1988.

Net-tel produced the first X400 electronic messaging systems for PCs. John led the company until venture capital investment in 2001, the company renamed Clearswift.