The future of some of Oxford's most popular artefacts - the shrunken heads at the Pitt Rivers Museum - could be in doubt.

The South American heads draw hundreds of visitors to the Victorian museum, in South Parks Road, and are particularly popular with children.

But museum curator Laura Peers - who questions the ethics of keeping and displaying the heads - is undertaking an "informal" review, which could lead to them being removed from display, or repatriated.

Author Philip Pullman, who featured the museum in the award-winning His Dark Materials trilogy, said: "I think the shrunken heads should stay".

Dr Peers, who has served on a Government-run working group on human remains, told the Oxford Mail she felt "uncomfortable" about the shrunken heads on display.

She added: "I personally would like to know more what the communities in Ecuador and Peru feel.

"We have never had a formal review of any particular display - this is an awkward area where personal views and professional training become mixed."

Dr Peers added she was trying to analyse visitors' responses to the heads, including those of children, but was not yet ready to arrive at any conclusions.

Dr Michael O'Hanlon, the museum's director, said: "The whole issue of human remains is, and has been widely debated in museums across the country.

"There are a range of legitimate perspectives people can take on this and, this being a university museum, we debate them.

"There are no plans at present to remove the shrunken heads from display, but the display has been changed recently and we will continue to keep it under review."

Margaret Dyke, spokesman for the Friends of the Pitt Rivers Museum, said: "I think the shrunken heads are the museum's number one exhibit.

"The children love them - they like being scared - and if they were removed the children would miss them."

Mr Pullman said he wanted the shrunken heads to stay and added: "The value of the shrunken heads is that they are real - you could replace them with plastic models but that would not be the same. It would be very hard to find the living relatives.

"I can understand the complexity of feeling about this, and we could be on the cusp of a cultural change regarding this kind of exhibit."

But he added: "The great value of the Pitt Rivers is the higgledy-piggledy nature of the displays, which itself is a window into the past, and the shrunken heads are part of that."