What is This?

on the wall of Leicester's Guildhalls courtyard
Clues
1 it has a small round hole in the bottom
2 As the notice reads It is not a bin
3 Guild members or the corporation would not have used it
4 The behind the scenes workers would

[Sue Cooper]

The first thing that came to mind was a urinal. Am I a bit crude?

[Margaret Snell]

@susiemc No Sue it is actually a late 19 century mop wringer.