Clerks of Works are the most highly qualified non-commissioned tradesmen in the Royal Engineers. The qualification can be held in three specialisations: Electrical, Mechanical and Construction. Clerks of Works are immediately promoted to Staff Sergeant on completion of the training course. Warrant Officers Class 2 hold the appointment of Clerk of Works Quartermaster Sergeant and Warrant Officers Class 1 hold the appointment of Clerk of Works Sergeant Major.