I propose Longton station on the Crewe-Derby line as a strong contender for Bleakest station. The station itself is quite bleak, and the surroundings are also very miserable.
It sits on a viaduct above the remains of the ailing town centre. The platform-level station buildings have been demolished, and the platforms blocked off part way along, making them too short for the occasional 4-car 158 or 170 services along the line (these only ever appear on quiet services, for reasons best known to EMR). Beyond the fences, the platforms are covered in brambles and litter. The station's elevated position means it is usually very windy, with just a small bus shelter on each platform for protection. At night, the lighting is quite ineffective. On the platforms, you feel simultaneously very exposed, yet also trapped. Platforms are accessed via dingy staircases, which loop back in on themselves, so you can't see the bottom of the staircase from the street, or from the platform, making them feel quite secluded and threatening. There are no lifts to platform level. Services are hourly, making it quite useless for local travel.
From the platforms, the view is spectacular. On one side, the decaying remains of the phoenix pottery works, a small patch of wasteland serving as a car park, a closed-down adult entertainment shop (good for catching things other than trains), a fire-gutted house, one of the worst-rated hotels in the country, and an empty churchyard (church long since demolished). On the other, the back of a Tesco Extra, an overgrown part-demolished bus station, a car wash run from a shipping container, a collapsing row of empty shops, the faded grandeur of the old town hall, and a very busy road junction. You will often find a group of addicts lurking under the bridge, or occasionally sleeping under the stairs to the platforms.
Positives: volunteers clean the station and tend to some flower boxes (many thanks for your efforts). These don't do much for the overall ambiance, especially at this time of year when everything is dead. There's some fading artwork on the viaduct walls. The in-use parts of the platforms are usually kept free of litter. Heading east from the station, the line crosses a fairly interesting old bridge.