A battered pot found in a garage in Cornwall, broken in antiquity and broken again and mended with superglue some 5,500 years later, was treasure – but the scruffy little cardboard label it held is now unlocking a lost history of finds from excavations in Egypt scattered across the world in the late 19th century.

The pot came with an odd family legend that back in the 1950s it was accepted in lieu of a fare by a taxi driver in High Wycombe. Alice Stevenson, curator at the Petrie Museum in London, which among its 80,000 objects has the original excavation records and hundreds of pieces from the same Egyptian cemetery, believes the story is true and may even have identified the mysterious passenger.