Boffins have discovered the remains of a hidden city two miles from Stonehenge, after creating digital maps of the ancient site to an unprecedented level of detail.

The researchers found 17 previously undiscovered religious monuments, as well as a huge burial mound, dozens of smaller ones and the remains of a timber building which may have been used to cut the flesh from bodies before they were put in the ground.

The ancients were also shown to have dug large pits, some of which may have been arranged to align with the stars, and drunk beer, judging by the presence of a load of ale pots.

The investigation was part of a scheme called the Stonehenge Hidden Landscapes Project, which was conducted by the University of Birmingham and the Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology,

"The rituals included exposure of the dead bodies, and defleshing on a large forecourt," said Wolfgang Neuber of the Ludwig Boltzmann Institute.

Many of the discoveries were focused around the Durrington Henge, a 4,500 year old settlement which was thought to be occupied for part of the year and used for feasting.

The new research found that this second henge was flanked by up a 330-metre long chain of huge stones, which are buried in the banks around the henge.

Up till now, we had absolutely no idea that the stones were there,” said Professor Vince Gaffney of Birmingham University.

The stones are about three metres long and 1.5 metres wide, although they are currently laying on their side, buried beneath the banks of the henge. It is thought they were brought to the site at some point around 2500BC and may have stood upright.

Gaffney said the site showed that ancient people had the same passion for redecorating as their modern-day descendants.

"They did lots of strange things. They killed monuments, changed them, reappropriated them. They developed over many hundreds of years, so the people who started them were not the people who finished them," he said.

To map Stonehenge and the surrounding area, the researchers used radar, laser scanners and magnetometers to scan up to three metres into the ground at a resolution of 10cm.

A programme called Operation Stonehenge: What Lies Beneath will cover the research. It is due to be broadcast on BBC Two at 20:00 BST on Thursday 11 September. ®