Had we not had a successful revolt against The Crown starting in 1776, slavery would have ended here in 1833, by act of Parliament, when it did for the rest of the British empire.
(Unless The South revolted against the full might of the entire Empire at that point!)
No emancipation without representation!
. . . assuming that the South had no influence on Parliament. I would argue its more likely that the American Revolution, by freeing the Empire of most of its slave holders, made that act possible or at least easier.Its an interesting counterfactual . . .