Human skulls, axes and knives are among the discoveries at an ancient monument within sight of Windsor Castle.

Archaeologists have uncovered the finds at what is thought to be a 5,500-year-old Neolithic gathering place.

The site at Riding Court Farm, near Datchet, less than two miles from the royal residence, could have been used for festivals, ceremonies and feasting, as well as trade.

John Powell, fieldwork director for Wessex Archaeology, called the remains ‘incredibly rare’ and added he expected more to be unearthed throughout the year.

He said: “The monument occupies a slightly raised area in what may have been a marshy or seasonably wet landscape within the Thames floodplain.

“Towards the base of the ditches, small concentrations of animal bone, pottery and worked flint have been found and probably relate to the activities that took place within the enclosure.

“The finds include finely worked flint arrowheads, knives and serrated blades, decorated pottery sherds and in one segment part of a human skull.

“A sparse scatter of internal features included a pit that contained a finely ground flint axe.”

The Thames Valley is thought to have been relatively heavily populated during the Neolithic period and similar monuments have been identified at Eton Wick, Dorney and Staines.

Archaeologists have also found evidence of prehistoric, Roman and later activity, indicating people periodically lived, farmed, settled and gathered in the area from the end of the last Ice Age, a period of about 12,000 years.