A projection of how the election results would look if we used Additional Member System (AMS), like in Scotland and Wales.
| Party | AMS | FPTP | Seat change |
|---|---|---|---|
| Labour | 236 | 411 | +175 |
| LibDems | 77 | 71 | -6 |
| Green | 42 | 4 | -38 |
| SNP | 18 | 9 | -9 |
| Plaid Cymru | 4 | 4 | 0 |
| Reform | 94 | 5 | -89 |
| Conservative | 157 | 121 | -36 |
| Northern Ireland | 18 | 18 | 0 |
| Other | 4 | 6 | +2 |
The Electoral Reform Society also favours STV, they probably chose AMS here as modeling it from FPTP isn’t complete guess work.
I actually wrote my thesis on analysing the 2019 election results and extrapolating vote choices for other systems and seeing how that would affect the balance of power in the UK .
Presumably part of that was trying to account for the lack of preference data?