LONDON - Ancient Britons devoured their dead and created gruesome goblets from the skulls of their remains, according to new research published on Wednesday.

Researchers from London's Natural History Museum discovered 15,000-year-old human bones in southern England which showed signs of cannibalism and skulls made into drinking cups.

The skulls -- found in Gough's Cave in the Cheddar Gorge in the southwestern English county of Somerset -- had been meticulously cleaned of soft tissue, cut to remove the base and facial bones, and had their rough edges smoothed to create skull-cups or bowls, palaeontologist Silvia Bello wrote in a study in the Public Library of Science journal PLoS ONE.

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"All in all it was a very painstaking process given the tools available," Bello said in a statement.

The researchers said the cups may have been used as containers or for some ritualistic purpose.

"It's impossible to know how the skull-cups were used back then, but in recent examples they may hold blood, wine or food during rituals," said Chris Stringer, who helped excavate one of the skull-cups in 1987.

At about 14,700 years old, the skull-cups from Gough's Cave are the oldest directly dated examples in the world, the researchers said.

They said the circumstances behind the deaths of the Cro-Magnons (European early modern humans), whose bones they discovered, can only be guessed at.

They may have been killed, butchered and eaten -- with the skull-cups just the end of this event -- or may have been part of the group who died and were eaten in a crisis situation, with the skull-cups created as a tribute to the dead.

"We simply do not know," they said in a joint emailed response to questions.

The use of skulls as drinking vessels has been well-documented in historical accounts and recent ethnographic studies, the researchers explained in their study.

Ancient Greek historian Herodotus portrayed the Scythians as people who drank from the skulls of their enemies and similar practices have been recorded among Vikings, Australian Aborigines and in tantric Buddhist rituals.

A precise cast of one of the skull-cups, complete with cut marks, will go on display in the Natural History Museum in London from March 1 for three months.