| Code | Name | Region |
|---|---|---|
| GBALL | Alloa | CLK |
| GBAL2 | Almeley | HEF |
| GBAOY | Almondsbury | SGC |
| GBASS | Alness | HLD |
| GBALM | Alnmouth | NBL |
| GBALW | Alnwick | NBL |
| GBAPN | Alperton | BEN |
| GBAPH | Alphington | DEV |
| GBNAD | Alresford | |
| GBARW | Alrewas | STS |
| GBALG | Alsager | CHE |
| GBALS | Alston | CMA |
| GBAHM | Altham | LAN |
| GBALP | Althorpe | NLN |
| GBALN | Alton | HAM |
| GBALQ | Alton | STS |
| GBAWO | Alconbury Weston | CAM |
| GBABH | Aldborough | NFK |
| GBADB | Aldbourne | WIL |
| GBALU | Aldbury | HRT |
| GBAOU | Aldebourne | WIL |
| GBALB | Aldeburgh | SFK |
| GBALH | Aldenham | HRT |
| GBALE | Alderley Edge | CHE |
| GBALR | Aldermaston | WBK |
| GBAER | Alderminster | WAR |
| GBGSR | Aldersgate | LND |
| GBALD | Aldershot | HAM |
| GBADH | Aldham | ESS |
| GBADT | Aldington | KEN |
| GBADG | Aldridge | WLL |
| GBAW6 | Aldworth | WBK |
| GBALX | Alexandria | |
| GBAFO | Alford | ABD |
| GBABX | Alford | LIN |
| GBALF | Alfreton | DBY |
| GBADL | Adlington | LAN |
| GBADO | Admaston | TFW |
| GBJDV | Adversane | WSX |
| GBAKS | Adwick Le Street | DNC |
| GBAGH | Aghadowey | CLR |
| GBZHG | Ahoghill | ANT |
| GBAWR | Ailsworth | CAM |
| GBAIN | Aintree | LIV |
| GBAMR | Aird Ma Ruibhe | AGB |
| GBADM | Aird Mhor (ardmhor) | ELS |
| GBAIR | Airdrie | NLK |
| GBAII | Airlie | ANS |
| GBAIH | Airth | FAL |
| GBAIT | Aith | ZET |