The historic Harwell computer, later known as the WITCH computer, comes out of storage this week to travel to The National Museum of Computing (TNMOC) at Bletchley Park where it will be restored to full working condition.

The historic Harwell computer, later known as the WITCH computer, comes out of storage this week to travel to The National Museum of Computing (TNMOC) at Bletchley Park where it will be restored to full working condition.
Once restored by the volunteers at the museum, it will be the oldest original functioning electronic stored program computer in the world and will be housed alongside the rebuild of Colossus Mk II, the world's first electronic computer.
The current earliest functioning computer is the 1956 Pegasus machine at The Science Museum in London.
The Harwell Computer dates back to 1949 when plans were drawn up for a machine to perform calculations then done by a team of bright young graduates using mechanical calculators.
The team's work had been so tedious that mistakes were inevitable, so the aim was to automate the work. Simplicity, reliability and unattended operation were the design priorities. Speed was a lower priority. The machine first ran in 1951.
"The machine was a relay-based computer using 900 Dekatron gas-filled tubes that could each hold a single digit in memory and paper tape for both input and program storage," said TNMOC director Kevin Murrell. "Its promises for reliability over speed were certainly met - it was definitely the tortoise in the tortoise and 