It is part of the Ashridge Estate, owned by the National Trust, and the local planning authority is Dacorum Borough Council.

At this time the North Sea covered much of south-east England and the site was in an inter-tidal area, but since then the Chiltern Hills have risen 170 metres.

This was the height of the last ice age, when the site was cold tundra like western Siberia today.

[3] According to Natural England the site is "controversial" as the new excavation shows gravel of possible marine origin rather than glacial till as previously believed.

These are the remains of working to extract the gravel during World War One to make sandbags of use at the front.