Well, pop the cap off and have a look. Did they hang the pipe off a pitless valve about 4 feet down? If so, make up a plug from cardboard and duct tape or similar on a rope and shove it down past where you want to cut it off. Wiring should come up and over the top of the casing. Hold it out of the way and with a cut wheel cut the bugger off and feed it up the wire and onto the ground. Slice a slot in it to free the wire and put the lid back on.
