Constituencies: O
8 constituencies
| Constituency | Nation | GSS code |
|---|---|---|
| Old Bexley and Sidcup | England | E14001414 |
| Oldham East and Saddleworth | England | E14001415 |
| Oldham West, Chadderton and Royton | England | E14001416 |
| Orkney and Shetland | Scotland | S14000051 |
| Orpington | England | E14001417 |
| Ossett and Denby Dale | England | E14001418 |
| Oxford East | England | E14001419 |
| Oxford West and Abingdon | England | E14001420 |