Witch at Bletchley: 'World's oldest working digital computer'
20 November 2012 Last updated at 00:17 GMT
The world's oldest working digital computer has been restored, and is now on display at the National Museum of Computing at Bletchley Park, Milton Keynes.
The BBC was given exclusive, early access to the newly restored machine.
Kevin Murrell, one of the people who discovered the computer, which was dismantled and kept in storage, explained how it was rebuilt.
With the help of Delwyn Holroyd, a project engineer at the museum who played a key role restoring the machine, he demonstrated that it is still in working order.