Might be something to do with it being flood plain, I think. Plus the ground is gradually tipping so that that area is becoming lower while the rest of the country is getting higher.
I still think that you wouldn't get them to Newcastle. Most southerners, i.e., south of Middlesbrough think that the entire north is one enormous pit heap, the people talk in unitelligible accents and all of us have whippets and pigeons.
just not a big enough catchment area to get 30-40000 a day in all seasons