Editing Pennant number (section)

===Second World War=== 
<ref>{{cite book |last1=Lenton |first1=H T |title=British and Empire Warships of the Second World War |date=1998 |publisher=Greenhill Books |location=London |isbn=1-85367-277-7 |page=713–25}}</ref>

====No flag superior====
Pendant number 13 was not allocated.
* Capital ships, aircraft carriers, modern cruisers

====Flags superior====
Pendant numbers 13 were not allocated to flag superiors. The letters J and K were used with three number combinations due to the number of vessels.
* D — [[destroyer]]s (until 1940), older [[capital ship]]s, [[aircraft carrier]]s, [[cruiser]]s (from 1940)
* F — destroyers (until 1940) and [[Armed merchantman|large auxiliary combatants]] (from 1940)
* G — destroyers (from 1940)
* H — destroyers
* I — aircraft carriers, cruisers (until 1940), destroyers (from 1940)
* J — [[minesweepers]]
* K — [[corvette]]s, [[frigate]]s
* L — [[escort destroyer]]s, [[sloop-of-war|sloops]] (until 1941)
* M — [[minelayer]]s
* N — minesweepers
* P — sloops (until 1939), boom defence vessels (until 1940)
* R — destroyers (from 1942), sloops
* T — [[river gunboat]]s, netlayers
* U — sloops (from 1941)
* W — tugs and salvage vessels
* X — special service vessels
* Z — gate, mooring and boom defence vessels
* 4 — [[Auxiliary ship|auxiliary]] anti-aircraft vessels
* FY — fisheries (auxiliary [[fishing trawler]]s, [[drifter (fishing boat)|drifter]] etc.)

====Flags inferior====
Flags inferior were applied to submarines. Royal Navy submarines of the "H" and "L", and some transferred American vessels, were not issued names, only numbers. In these cases, the pendant number was simply the hull number inverted (i.e. ''L24'' was issued pendant "24L"). Pre-war photos show the pendants painted correctly, with the flag inferior, but wartime photos show that the numbers tend to be painted "backwards", in that the inferior was painted on as a superior. For obvious reasons, the inferior "U" was not used so as not to confuse friendly ships with [[Nazi Germany|German]] [[U-boat]]s. For similar reasons "V" was not used. Pendant numbers 00–10, 13, and those ending in a zero were not allocated to flag inferiors.
* A — allied (Polish [[ORP Orzeł (1938)|ORP ''Orzeł'' (85A)]])
* C ("coastal") — {{sclass2|U|submarine|4}} (pre-war construction)
* F ("fleet") — {{sclass2|River|submarine|4}}
* H — [[British H-class submarine|H class]]
* L — [[British L-class submarine|L class]]
* M ("minelayer") — {{sclass|Grampus|submarine|4}}
* N — allocated to existing submarines after 1940.
* P — [[Odin-class submarine|O class]], [[Parthian-class submarine|P class]]
** 31P— U class (wartime construction), [[British V-class submarine|V class]]
** 211P to 299P — [[British S-class submarine (1931)|S class]] (wartime construction)
** 311P to 399P— [[British T-class submarine|T class]]
** 411P to 499P— [[Amphion-class submarine|A class]]
** 511P to 599P— [[United States Navy]] [[lend-lease]] submarines
** 611P to 699P— commandeered foreign construction
** 711P to 799P— captured enemy submarines
* R — [[Rainbow-class submarine|R class]]
* S — S-class submarines (pre-war construction)
* T — T-class submarines (pre-war construction)