A druid leader is calling for fake human remains to be put on display at Stonehenge instead of real ones.
King Arthur Pendragon criticised a "macabre" plan by English Heritage to display "ancestral remains".
In 2011, King Arthur lost a High Court legal battle to have bones, which were discovered in 2008, returned to their original resting place at the popular Wiltshire attraction.
English Heritage said the remains were not from the 2008 excavation and their "presentation, treatment and storage" would follow strict UK guidelines. The cremated remains of more than 40 bodies, thought to be at least 5,000 years old, were removed from a burial site at the ancient stone circle five years ago.
King Arthur, who styles himself the Battle Chieftain of the Council of British Druid Orders and Titular Head and Chosen Chief of the Loyal Arthurian Warband Druid order, maintains the bones were the remains of members of the "royal line" or "priest caste" who could have been the "founding fathers of this great nation".
In an open letter, he said: "It is with sadness and regret that I recently learned of English Heritages plans to put on display in 'their' new visitor centre at the World Heritage site of Stonehenge, ancient skeletal and cremated human remains excavated from the environs of the World Heritage site.
"This is not only out of step with the feelings of many of the peoples and groups that I represent who would rather the ancient dead were reburied and left to rest in peace and where appropriate samples kept for research and 'copies' put on display, but is surely against the driving cultural principles of a UNESCO World Heritage Site. English Heritage has missed an opportunity to be world leaders in this field but instead have opted to display the ancestral remains in such a macabre manner."
King Arthur, a 59-year-old former soldier who changed his name by deed poll, added: "We shall not take this development lightly and will oppose any such intention by English Heritage at Stonehenge."
The £27 million project to build a new visitor centre and close the road alongside the ancient monument, near Salisbury, is due to be completed by the end of the year.
A spokeswoman for English Heritage said visitor research showed the "vast majority of museum visitors are comfortable with, and often expect to see, human remains".