I think people moving away from Labour will go for Greens or Reform mostly.
So, if we take our now free-floating Labour voter, what is it that they are repelled from Labour by to be either attracted to Reform, or Green with equal tension ?
And from that what proportion will go to Reform and which proportion will go to Greens ?
If we slice into the numbers that voted Labour in 2024 after not voting Labour in 2019, how would that translate into polling ? And how does it overlay the cultural geography of England, Scotland and Wales ?
Without being arsed to provide too much workings, it looks like of the "new" Labour voters in 2024, 75% would not necessarily re-vote Labour. With a split of about 1 in 5 moving to reform, 1 in 5 to LibDems and 3 in 5 moving to Greens.
One possible future is that Reform become a reactionary counterpoint to the LibDems, and overperform locally and underperform nationally.