Royal Artillery Mechanised Batteries 1st prize driving skill badge. Extended to Royal Engineers and Royal Corps of Signals units in 1936. One per unit. Not subject to competition during WW2 and (semi-officially) signified driving instructors during that period. Worn lower left arm. Described Army Council Instructions 1927, obsolete 1950.
This example, 68mm tall, 49mm wide. Embroidered in black and white thread on a khaki backing – A black rimmed steering wheel with a black ringed centre boss with four white spokes. above, an imperial or king’s crown in white.
See: Edwards D. & Langley D., British Army Proficiency Badges (Wardley Publishing) 1984, page 71-72