Staff sergeant
On 11 January 1879, a Royal Warrant established conductors of supplies (in the Army Service Corps) and conductors of stores (in the Ordnance Store Branch) as warrant officers, ranking above all non-commissioned officers. In 1892, conductors of supplies were renamed staff sergeant majors 1st class, but conductors of stores remained in what in 1896 became the Army Ordnance Corps. Staff sergeant majors in the new corps were renamed sub-conductors. In February 1915, with the general introduction of warrant officers throughout the army, conductors and sub-conductors became warrant officers class I. Sub-conductors reverted to the appointment of staff sergeant major in 1967, but the appointment of conductor passed to the new Royal Logistic Corps in 1993.