On 16 September 1946, with Germany broken into four, the Robertson-Malinin Agreement came into effect to allow the free movement of military representatives from all four nations across the border.
From this, the four military liaison missions were created: the American USMLM, the French FMLM, the Soviet SOXMIS and the British BRIXMIS.
BRIXMIS were allocated 31 passes allowing 31 members to cross the border into East Germany. They had to wear uniform and drive marked vehicles.
What was BRIXMIS and who were the spies?
Read more by clicking on 'Find Out' at the top of this page, or watch the Real Cold War Spies: BRIXMIS series on Youtube.