Synopsis
Blue Peter continues the mission to find CBBC Intelligence Officers. Over 5000 viewers applied but only three get the chance to go inside MI5's Headquarters.
Further Information
Similar broadcast resources
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.