Birmingham University has returned various skulls & bone fragments to the Salinan tribe in San Luis, Obispo County, California, where they have been re-buried.
Returns of artefacts involving human remains  from institutions in the UK have now become commonplace (although there are still many more cases awaiting consideration). Pressure from the British Museum has made sure that these are differentiated from those that don’t involve human remains. So, whereas once, they said nothing could be returned, when faced with political pressure, they categorised their collection, to allow some of it to be returned, but make no difference to the case for retaining the rest of it. One could cynically argue, that this particularly appealed to them, as they had almost no items in their collection  involving human remains (most of those were taken by the Natural History Museum in London when it was split off as a separate institution).
Only certain museums in the UK are covered by the Human Tissue Act , but once these institutions started making returns, the cultural climate shifted, paving the way for many more institutions to follow their lead.
So, the return of human remains is now relatively accepted (as is the one for items looted during the holocaust AKA Nazi Era) – but the campaign still needs to be won for the many other disputed artefacts that have the misfortune in not being in either of these special categories.
Los Angeles Times 
Native American skulls repatriated to California from England
How seven skulls from a California tribe got to the University of Birmingham is unclear. But their return appears to be the first event of its kind in the state.
By Steve Chawkins, Los Angeles Times
May 20, 2012
Nobody thought much about the locked metal cabinet in the medical school at the University of Birmingham in the United Kingdom. It was another forgotten fixture in the anatomy department — until a researcher last year found seven skulls with yellowing labels indicating the remains were those of Native Americans from California’s Central Coast.
Earlier this month, the skulls and several bone fragments were boxed and gingerly placed aboard a jet to LAX at London’s Heathrow Airport. In a quiet ceremony, they were reburied in San Luis Obispo County, more than a century after their odyssey began.
“They didn’t volunteer to leave the U.S.,” said John Burch, a spiritual leader of the tiny Salinan tribe. “They were kidnapped, and now they’re home.”
Repatriation, the return to tribes of indigenous bones and artifacts, is not always a smooth road. A 1990 federal law, the Native American Graves Protection and Repatriation Act, calls for museums and other institutions to give remains and relics back to federally recognized tribes that request them. The process, however, is cumbersome for tribes and frustrating for scientists who believe certain items should remain accessible for study.
The act and similar state laws do not apply to foreign institutions. Still, the University of Birmingham, among others, sees repatriation as “a moral choice,” said June Jones, a bioethicist in the university’s School of Medical and Dental Sciences. The school also is returning aboriginal bones to Australia and Maori bones to groups in New Zealand.
“This is an honor,” Jones said. “It’s all about respect for cultures and beliefs, even if they don’t happen to be ours.”
How and when the Salinan bones got to Birmingham is unknown. The only clues came from the handwritten labels: “Dug from a grave near Avila, San Luis Obispo County, California by R.W. Summers.”
Summers was an Episcopal minister in San Luis Obispo from 1881 until his death in 1898. He was also an avid amateur archaeologist who assembled an extensive collection of Native American relics.
In his journals, he wrote of finding skeletons and “ornaments of stone, bone and shell … placed in the grave by loving hands, that the departed warrior might appear well in the happy spirit-land.” Some believe he also may have acquired bones from workers who were excavating for railroad tracks.
Summers’ collection wound up with his friend, a British clergyman and fellow archaeology buff named Selwyn Freer. Much of it was later acquired and is still held by London’s venerable British Museum. But the skulls somehow came to rest at the university in Birmingham, where Freer’s family had been prominent for centuries. There is no indication they were ever studied, Jones said.
Searching for their home, Jones emailed the Santa Ynez band of Chumash Indians and the Salinans, groups whose ancestors are known to have lived in the area. Burch, the Salinan elder, responded. With the help of Sen. Dianne Feinstein (D-Calif.),the U.S. Embassy in London and the state’s Native American Heritage Commission, Burch navigated a thicket of bureaucracy.
“Getting remains into the U.S. has been very problematic,” said Dave Singleton, a program analyst with the heritage commission. “As far as we know, this is the first of its kind in California.”
Singleton said the Chumash have expressed interest in asking the British Museum to repatriate the more than 200 items still there.
On May 9, Jones and her carefully packed cargo touched down at LAX. She and Chris Molina, another official of the 700-member Salinan tribe, piled into the front of a pickup truck, while Burch climbed into the crew cab with a heavily taped cardboard box the size of a small trunk. It bore a wine-glass sticker that read “Fragile.”
“I was sitting in the back, with the ancestors,” Burch said.
Up the coast in San Luis Obispo, anthropologist Robert Hoover was waiting at the coroner’s office. A professor emeritus at Cal Poly, Hoover identified the skulls as “pretty clearly Native American.” One sign was the shovel-shaped incisor teeth typical of Native Americans; another was a pattern of wear consistent with grit in the early Native American diet.
The remains were “prehistoric,” Hoover said. To avoid damaging the bones, no DNA or other testing has been performed.
At a ceremony in a serene, secret spot where other Native Americans are buried, Burch said a few words. There was subdued drumming. He faced a crowd of about 25 tribal members, and a few local officials looked on. The skulls were laid in the ground facing west.
“They’re home,” Burch said.