Most councils leave it to the allotment committees to police the sites.

Committee men go to the allotment for the same reason as most of us do, not to be policemen.

Most allotment sites aren't run efficiently, never have been, and unless the council employ full time paid staff to run the sites as they should be, including evicting plot holders who are not utilising their plots, the status quo will continue!

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My Majesty made for him a garden anew in order
to present to him vegetables and all beautiful flowers.- Offerings of Thutmose III to Amon-Ra (1500 BCE)