Britain’s departure from the EU and the renewed focus on empire should prompt a “significant shift” in its approach to returning sacred artefacts to Indigenous communities, the head of an Australian government-funded project has said. More than 33,000 items of Indigenous Australian heritage are held in UK museums, including some believed to have been stolen during or shortly after Captain James Cook’s first voyage to Australia 250 years ago. Manchester Museum became the first UK institution to return some of these objects in a powerful handover ceremony in November. Yet despite a growing restitution movement, many leading British museums have appeared reluctant to hand over sacred artefacts because of concerns about the wider implications for their collections. Craig Ritchie, who runs what is believed to be one of the world’s biggest repatriation projects, said Brexit and the renewed focus on Britain’s imperial history represented a powerful moment to reassess the UK’s relationship with Indigenous Australians so that it “isn’t just one where we happen to share a monarch and isn’t just one where we are interested in trade deals”. He said: “If it’s true that Brexit is more than simply getting out of some kind of political union with Europe and is, in fact, an expression of the UK trying to rethink its place in the world independent of Europe, then part of that is the opportunity to rethink and recalibrate the relationship between the UK and its former colonial dominions and … the indigenous people in those former colonies”. Ritchie is head of the Australian Institute of Aboriginal and Torres Strait Islander Studies (Aiatsis), which is funded by the Australian government and has identified more than 100,000 sacred artefacts and cultural material in institutions around the world, of which a third are in the UK. Although Aiatsis hopes to return as many artefacts as it can, Ritchie said: “Not everything will come home and probably not everything should,” adding that it was willing to explore alternative arrangements with UK institutions. However, he said the final resting place of the objects was “a decision that should be made by the community of origin rather than just a recalcitrant white institution that’s refusing to give stuff back”. The Pitt Rivers Museum, which displays the University of Oxford’s archaeological and anthropological items, has the biggest collection of this material in the UK with about 16,000 pieces. The museum works with Aiatsis to help understand the material and is known for engaging with indigenous peoples. Cambridge University’s Museum of Archaeology and Anthropology has the UK’s second largest collection of indigenous items, with about 3,000 artefacts, and the British Museum is believed to have about 2,900 in its collection. Ritchie said the institute’s discussions with the British Museum, which has previously been reluctant to permanently return relics to Australia, were going to be “a longer process” and that it would have to “step our way through what could easily become quite a minefield of politics and tricky questions”. The then culture secretary, Jeremy Wright, last year ruled out any change in the law to allow national museums to return objects to their countries of origin. Arts Council England is due to publish updated guidance this year on the repatriation of cultural objects, superseding existing guidance produced by the defunct Museums and Galleries Commission in 2000. Of the 38 UK institutions that responded to an Aiatsis survey two years ago, 17 said they were willing to consider a return request and most said they were happy to share information about their collections. Ritchie said the confluence of events surrounding Brexit, the renewed focus on Britain’s colonial legacy, and the successful repatriation by Manchester Museum would herald a significant shift in the approach of many UK institutions.