There was an enquiry from someone on TMA a while back about the standing stone alleged to have been discovered at Stansted Airport. At the time, I could find out nothing about it. However, this may be it.
Recently placed on the green at the crossroads in nearby Takeley (just outside the airport) is a sarsen stone found at a Bronze Age site at Stansted Airport. Sarsen is only found in Essex as an uncommon glacial erratic. However, the sharp edges and polished surfaces seems to indicate human intervention and dressing. It seems inconceivable that such a regular "square" stone could become that shape from the action of ice and after being dragged along in a glacier. Found on the site of a Bronze Age settlement so it is likely to have had some significance, possibly as a standing stone.
Photos can be seen at: