| U | Leeds |
| UA | Leeds |
| UB | Leeds |
| UC | London (Central) |
| UD | Oxford |
| UE | Dudley |
| UF | Brighton |
| UG | Leeds |
| UH | Cardiff |
| UJ | Shrewsbury |
| UK | Birmingham (Wolverhampton until 1974) |
| UL | London (Central) |
| UM | Leeds |
| UN | Denbighshire prior to 1974, Barnstable 1974–80, Exeter from 1981 |
| UO | Exeter (Barnstaple until 1980) |
| UP | Newcastle upon Tyne (Durham until 1981) |
| UR | Luton (Hertfordshire until 1974) |
| US | Glasgow |
| UT | Leicester |
| UU | London (Central) |
| UV | London (Central) |
| UW | London (Central) |
| UX | Shrewsbury |
| UY | Worcester |