I love this seasonal thread. I doubt that my nomination this year will cause any controversy, it's the Bright Helm in Brighton. I found just about everything about this place to be awful, which is a shame as I thought their Post & Telegraph nearby was pretty good apart from being packed.
I made the mistake of visiting a local pub with no reviews, so I can also offer a non-spoons contender the County Arms at Highams Park in E4. It's not as awful as the Bright Helm but nevertheless is a complete waste of time.