Purfleet, Essex.
Rented a just finished new build, really nice, modern, spacious flat. There wasn't really much in the area other than a nice pub, an industrial estate and a train station. Other side of the train tracks was a horrific council estate, one of the worst in Essex, but it was far enough away from me that I didn't have to worry. Was quite comfortable there for the first 3 months... and then the landlord next door rented his place to the council. This was a new build flat, pristine, I was paying £750 a month for mine (18 years ago).
The guy that moved in was young, jobless, liked to stay home and get drunk but his Mrs was the worst. They were an awful couple, they would beat the **** out of eachother, not just him hitting her, but abuse both ways. I remember an ambulance being called when she glassed him... and they would argue all the time. She would scream obscenities at him at the top of her lungs, it would spill out into the corridor and into the outdoor spaces. Police were called at least 3 times a month, the worst neighbors you can imagine (even worse than my gypsy neighbor who stabbed me!). All came to a head when I caught him trying to break into my postbox to steal my post, we ended up in an altercation, luckily by this time I was at a point I could give notice on my tenancy and decided to move.