UK and US officer ranks compared Not listed are U.S. warrant officers. A warrant officer is an officer who can and does command, carry out military justice actions and sits on both selection and promotion boards. A US warrant officer is a single-track specialty officer, initially appointed by their respective service secretary; he/she receives a commission upon promotion to chief warrant officer two (CW2). In the UK the separation between "other" ranks and "officer" ranks can, on occasion, become permeable. Within the British armed services, both Sir Fitzroy Maclean and Enoch Powell are examples of, rare, rapid career progression with the British army, both rising from the rank of private to brigadier during World War II. In the US military such advancement is not uncommon, all five services maintaining programs that select promising enlisted men and women for the commissioned ranks. Notes to tables above The Royal Marines rank alongside their army equivalents. However, when on the books of any HM Ship or Naval Establishment, Royal Marines are subject to the Naval Discipline Act 1957. In those circumstances, many officer ranks in the Royal Marines formerly enjoyed greater status. Second lieutenants were equivalent to sub lieutenants and ranks from lieutenant to major were considered equivalent to one rank higher (OF-2 to OF-4). Lieutenant colonels were considered equivalent to RN captains with less than six years in the rank, and colonels were equivalent to captains with more than six years seniority. Higher ranks followed the equivalence on the table above. This state of affairs ended on 1 July 1999, when Royal Marine officer ranks were fully aligned with those of the army. RAF-style ranks are also used by the Royal Australian Air Force, Royal New Zealand Air Force, Nigerian Air Force, Indian Air Force, Pakistan Air Force, Bangladesh Air Force, Hellenic Air Force, Egyptian Air Force, Trinidad and Tobago Air Guard, Royal Air Force of Oman and Sri Lanka Air Force. The Ghana Air Force and Air Force of Zimbabwe (previously Royal Rhodesian Air Force) also use the same basic system, but replace pilot officer and flying officer with air sub lieutenant and air lieutenant. The Royal Thai Air Force uses the RAF ranks also. The Royal Canadian Air Force and Royal Malaysian Air Force also previously used the system. The U.S. military usually uses O-1 to O-10 to denote officers, and not the NATO codes of OF-1 to OF-10 in