Roman glass sets auction record

It was bought by a telephone bidder.

The Constable-Maxwell cage-cup dates from the third century and is decorated with a delicate lattice design. It has survived intact for 17 centuries.

It is the third time the item has set the record for the highest price paid for a piece of ancient glass.

Joanna van der Lande, head of antiquities at Bonhams, said it was likely the glass bowl, thought to have been a grave object, would have originated in the eastern Mediterranean.

Ms van der Lande added: "It's exceptionally fragile and cut from a single block of glass.

"It's something that would have been highly important in its day.

"It would have been clear, but has become iridescent due to a chemical reaction between the earth and the glass.

"Its probable use was as an oil lamp suspended by a metal collar around the rim and light would have come through the lattice work.

"It's really a very highly prized piece."