| Y | Somerset |
| YA | Taunton |
| YB | Taunton |
| YC | Taunton |
| YD | Taunton |
| YE | London (Central) |
| YF | London (Central) |
| YG | Leeds |
| YH | London (Central) |
| YJ | Brighton (Dundee until 1974) |
| YK | London (Central) |
| YL | London (Central) |
| YM | London (Central) |
| YN | London (Central) |
| YO | London (Central) |
| YP | London (Central) |
| YR | London (Central) |
| YS | Glasgow |
| YT | London (Central) |
| YU | London (Central) |
| YV | London (Central) |
| YW | London (Central) |
| YX | London (Central) |
| YY | London (Central) |