A circle of deep shafts has been discovered near the world heritage site of Stonehenge, to the astonishment of archaeologists, who have described it as the largest prehistoric structure ever found in Britain.

Four thousand five hundred years ago, the Neolithic peoples who constructed Stonehenge, a masterpiece of engineering, also dug a series of shafts aligned to form a circle spanning 1.2 miles (2km) in diameter.

The structure appears to have been a boundary guiding people to a sacred area because Durrington Walls, one of Britain’s largest henge monuments, is located precisely at its centre.

Gaffney said: “The size of the shafts and circuit surrounding Durrington Walls is currently unique.

It demonstrates the significance of Durrington Walls Henge, the complexity of the monumental structures within the Stonehenge landscape, and the capacity and desire of Neolithic communities to record their cosmological belief systems in ways, and at a scale, that we had never previously anticipated.”