| Name of System | Type? | Where? | When? |
|---|---|---|---|
| FPTP | Plurality | Westminster/Local | |
| AV (alternate vote) | Majoritarian | ||
| SV (supplementary vote) | Majoritarian | Mayoral (currently FPTP, Labour plans to reform) | |
| STV | PR | NIA, Scotland Loacl | |
| Regional (closed) List | PR | European Elections (except NI) | |
| AMS | Mixed | Scotland, Wales |