For the first time in more than 60 years a Colossus computer is cracking codes at Bletchley Park.

The machine is being put through its paces to mark the end of a project to rebuild the pioneering computer.

It is being used to crack messages enciphered using the same system employed by the German high command during World War II.

The Colossus is pitted against modern PC technology which will also try to read the scrambled messages.