| Code | Name | Region |
|---|---|---|
| GBAYA | Aylesbeare | DEV |
| GBAYL | Aylesbury | BKM |
| GBAYS | Aylesford | KEN |
| GBAYE | Aylesham | KEN |
| GBAYT | Aylestone | LCE |
| GBAYH | Aylsham | NFK |
| GBAON | Aston | ROT |
| GBASN | Aston | WOK |
| GBAOW | Aston Cantlow | WAR |
| GBATN | Aston Clinton | BKM |
| GBASV | Aston Somerville | WOR |
| GBATM | Atcham | SHR |
| GBATF | Athelstaneford | ELN |
| GBATA | Athena Fpso | |
| GBATH | Atherstone | WAR |
| GBATR | Atherton | WGN |
| GBATT | Attenborough | NTT |
| GBATC | Attercliffe | SHF |
| GBAWL | Attleborough | NFK |
| GBAUK | Auchinleck | EAY |
| GBAUC | Auchnacraig | AGB |
| GBACH | Auchterarder | PKN |
| GBAHH | Auchterhouse | ANS |
| GBAMU | Auchtermuchty | FIF |
| GBAKL | Auckengill | HLD |
| GBAUD | Audenshaw | TAM |
| GBAHE | Ashtead/london | SRY |
| GBAHT | Ashton | CHW |
| GBASM | Ashton In Makerfield | SHN |
| GBAKY | Ashton Keynes | WIL |
| GBASL | Ashton Under Lyne | TAM |
| GBAHS | Ashurst | HAM |
| GBAWA | Ashwater | DEV |
| GBASW | Ashwell | LEC |
| GBAWP | Ashwellthorpe | NFK |
| GBAIF | Askam In Furness | CMA |
| GBARK | Askern | DNC |
| GBASQ | Askham | CMA |
| GBALC | Aslacton | NFK |
| GBASP | Aspall | SFK |
| GBAXP | Aspatria | CMA |
| GBAPU | Aspull | MAN |
| GBATX | Astley | WOR |
| GBAAB | Astley Abbotts | SHR |
| GB2AB | Aston | BIR |
| GBASO | Aston | HRT |
| GBART | Artigarvan | STB |
| GBARU | Arundel | WSX |
| GBASC | Ascot | WNM |
| GBAQO | Ash | KEN |