Hey Tealeaf, how come, when you are a Church man, do you know about things in the Manchester Road area of Accrington?
It is indeed a boundary stone, and is sited at what I call the "top end" of Royds Avenue, just below Hollins School. I suppose its correct siting is "Junction of Royds Avenue/Hollins lane.
I have to say you are totally correct Weary Tourist with your assumption that the initials stand for
Boundary Stone Urban District Council 1877.
It is indeed a boundary stone, there should also be one in the garden wall at "Greenmount" 235 Manchester Road. There should be a third one in the wall, facing down the space between 140 and 142 Southwood Drive, Baxenden.
Atarah