BATCO, short for Battle Code, is a hand-held, paper-based encryption system used at a low, front line (platoon, troop and section) level in the British Army during the late Cold War period.
A BATCO sheet is composed of a double-sided sheet of about A5 that fits in a specially made BATCO wallet, and is used at unit and formation level. Each single side is usually valid for 24 Hours.
In addition to the code card there is:
BATCO is similar to Slidex but more recent and just about obsolete due to the introduction of secure radio Bowman. The use of BATCO is still taught to Royal Signals Communication Systems Operators as a back-up should secure equipment fail or be unavailable. It is also taught to Army Cadets and Combined Cadets as part of the Signal Classification qualification. BATCO documents are classified as "Restricted" information.