Centenary of the birth of WWII code breaker Alan Turing
20 June 2012 Last updated at 18:45 BST
This week sees the 100th anniversary of the birth of Alan Turing, a man regarded as one of the most influential mathematicians of the 20th Century.
He is best known for his work cracking the Germans' secret codes during the Second World War.
He is also regarded as one of the pioneers of computer technology.
An exhibition devoted to his life and achievements opens at the Science Museum in London on 21 June.
The BBC'S Technology Correspondent, Rory Cellan-Jones, was granted an exclusive preview.