Sergeant major instructor

Sergeant major instructor (SMI) is a British Army appointment held by warrant officers class 1 in the Small Arms School Corps and the Army Physical Training Corps and by some WO1s in the Royal Engineers.

Cadet forces

It is also a rank held by some of the civilian^[1] adult instructors in the Army Cadet Force, ranking between staff sergeant instructor and regimental sergeant major instructor.^[2] SMIs of the ACF do not hold a warrant and thus are not warrant officers, although their badges of rank are similar to those of an army warrant officer class 2.^[3][4]