Oldest working digital computer

Oldest working digital computer
Who
Harwell Dekatron Computer (aka WITCH)
Where
United Kingdom (Milton Keynes,Bletchley Park,National Museum of Computing)
When
2012

First used in April 1951, the Harwell Dekatron Computer (also known as WITCH - Wolverhampton Instrument for Teaching Computation from Harwell) is the oldest working electronic computer in the world. Currently located at the National Museum of Computing, Bletchley Park, UK, the computer underwent a complete restoration from September 2009 to November 2012.