I managed to get out of London enough this year to have a few great contenders for POTY - in no particular order:

The Three Pillars, Gravesend
Holly Bush Inn, Makeney
The Sun, Pickering
The Waiting Room, Whitby
The White Swan, Stokesley
Rock, Chiddingstone Hoath
Wonston Arms, Wonston

But the best of the bunch happened to be my final pub of 2021 - The Brewery Tap, Abingdon.