Project Petra Launch | Blue Peter
Blue Peter launches a search to find CBBC intelligence officers. Also, Radzi attempts a daring dive with the help of 14-year-old athlete, Matthew Dixon.Tweet
Project Enigma - Cracking codes in London | Blue Peter
The competition winners use a replica working Enigma machine to crack their own puzzle set by GCHQ.
Project Enigma - GCHQ Tour and challenge | Blue Peter
The competition winners, get their first look inside GCHQ and are given their top-secret mission to crack.