Egyptian authorities are calling for the British Museum to return the 2,000-year-old Rosetta Stone to Cairo.
The Rosetta Stone dates from 196 BC
The artefact is one of the British Museum's most prize pieces, helping to attract millions of visitors each year.
The stone was discovered in 1799 at the mouth of the Nile and provided a key insight into hieroglyphics because it was accompanied by the Greek translation.
The French yielded it to the British in 1801 and it has been housed in the British Museum since 1802.
The Egyptian Government is now asking the UK to loan it to the Cairo museum for a three-month period, something the British Museum is unlikely to grant, with a view to taking it back for good.
Vivian Davies, Egyptian curator at the British Museum, told BBC News: "What curator in the British Museum would actually want to see leave an object that is absolutely core to our function as an institution that not only presents Egyptian antiquities but also Egyptian antiquities as a part of the civilisation of the world."
There are Egyptian antiquities in museum collections around the world, with the Berlin Museum holding the bust of Queen Nefertiti - another relic Egypt wants returned.
The Greek Government has continually been rebuffed over its pleas to the British Museum to hand over the ancient Elgin Marbles frieze.