Warrant officer
In the British Army, there are two warrant ranks, warrant officer class two (WO2) and warrant officer class one (WO1), the latter being the senior of the two. These ranks were previously abbreviated as WOII and WOI (using Roman instead of Arabic numerals). "Warrant officer first class" or "second class" is incorrect. The rank immediately below WO2 is staff sergeant (or colour sergeant). From 1938 to 1940 there was a WOIII platoon sergeant major rank.