Harwell Computer

The Harwell computer, also called the Harwell Dekatron computer and later known as the Wolverhampton Instrument for Teaching Computing from Harwell, is an early British computer of the 1950s built from valves and relays at the Atomic Energy Research Establishment in Harwell. Construction began in 1949, it became operational in April 1951 and was handed over in May 1952, and it remained in service until being decommissioned in 1973. Following restoration at the National Museum of Computing between 2009 and 2012, the Guinness Book of World Records recognized it in 2013 as the world's oldest working digital computer, a title it had already held for several years before its original decommissioning.