I grew up in a town called Burnley in east Lancashire. I'm not saying it's the grimmest place in the whole country but to my mind it's a strong contender.
First off, the weather. Burnley is an ex-cotton town (industry now obviously totally dead after it all went to India) and the story goes that cotton snaps less when there's a lot of moisture in the air, so they built the mills in the wettest part of the country. So it absolutely shits down at all times and is the only place I've ever been in my life where it rains horizontally
Second, it's half Muslim and there is zero integration, it's as though there were a line drawn down the middle of the town, BNP on one side and Islam on the other. Once our mate was stopped by the police while playing Asian Dub Foundation in his car and the police asked him "why are you playing paki music"
Third, the inhabitants of Burnley all wear a permanent gormless, slack-jawed expression as though they don't understand. I found them very small-minded and also violent of course, for example my brother had his arm broken on Christmas Eve in Blackburn (the next town along) this is no joke, Burnley is not far from Rochdale where there was the very sad case of Sarah Lancaster who was kicked to death simply for being dressed as a goth
someone mentioned cider drinking - there were some kids who used to hang out in a village called Whalley, one of them had a kid and i saw her down the park with a bottle of cider in the pram with the baby
In short not a place for people like me and I got out at the earliest opportunity.