"Sink Hole" or "Bore Hole"?

"Sink Hole" found in School Lane Garden?

Yesterday (Saturday) I fell into this hole in my garden, very dangerous hidden by many weeds, (like the rest of the garden).

Could it be a sink hole? 2ft deep and 2ft diameter straight sides, looks almost a machine bored hole.

How did it get there?

Is it a coincidence that 'Airband' installed a telegraph pole nearby recently? And why is it in my garden when the pole is the other side of the hedge by the kerb on the corner of School lane?

Conspiracy theorists feel free....