Latest YouGov poll:

22% - Labour
17% - Tories
28% - Reform
16% - Lib Dem
12% - Green
3% - SNP
1% - Plaid Cymru
3% - Others

So that's 54% for a left-wing coalition (Lab, Lib Dem, Green, SNP, Plaid), 45% for a right-wing coalition (Tories, Reform) and 3% others. (That's more than 100% but that's probably because of rounding.)

I think people underestimate the left-wing. A majority of Brits support the left.

Source: https://en.wikipedia.org/wiki/Opinion_polling_for_the_next_United_Kingdom_general_election#2025