It was worked between c. 2600 and c. 2300 BCE, although production may have continued through the Bronze and Iron Ages and later, owing to the low cost of flint compared with metals.

The scheduled monument[1] extends over an area of some 37 ha (91 acres) and consists of at least 433 shafts dug into the natural chalk to reach seams of flint.

It has been calculated that more than 2,000 tonnes of chalk had to be removed from the larger shafts, taking 20 men around five months, before stone of sufficient quality was reached.

This is probably what inspired the later Anglo-Saxon inhabitants of the area to name it after their god Grim (literally the masked, or hooded one, a euphemism for Woden).

The medium-depth shafts yielded as much as 60 tons of flint nodules, which were brought to the surface and roughly worked into shape on site.

The axes were much in demand for forest clearance and settlement, development of farmland for arable crops and raising animals, which characterises the Neolithic period.

However, it is possible that the Venus figurine and the phallus are modern fakes – there is a lack of primary evidence surrounding their recovery in 1939, and rumours circulated at the time of the excavation that they were planted in order to deceive Leslie Armstrong, the archaeologist overseeing the dig.

Assuming no more than two shafts were open at any one time, around 120 red deer may have needed to be bred and managed nearby, in order to provide a steady supply of antler as well as skin, food and other products that the miners would require.

However, it is probably relevant that Grime's Graves were close to the very rich soils of the Fens, and forest clearance here would rely on local products.

Doctor Philip Harding FSA, later to appear in the TV programme Time Team, dug the site each summer from 1972 to 1976.