Conductor (Cdr) is an appointment held by a few selected warrant officers class 1 in the Royal Logistic Corps and is one of the most senior appointments that can be held by a warrant officer in the British Army. Previously conductor was the most senior warrant officer appointment, but it was outranked with the creation of the Army Sergeant Major appointment in 2015 following Army reforms. The appointment was also reintroduced into the Royal Australian Army Ordnance Corps for selected warrant officers class 1 in 2005.
The first known mention of conductors is in the 1327 Statute of Westminster, when they are mentioned as the men whose job it was to conduct soldiers to places of assembly. The "Conductor of Ordnance" is mentioned in the records of the siege of Boulogne in 1544 and conductors are mentioned several times in surviving records from the 17th century. In 1776 they are described in Thomas Simes's book The Military Guide for Young Officers as assistants to the Commissary of Stores. The Land Transport Corps and the Military Stores Department of the 19th century both included conductors in their strength.
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.