As detectives and forensic scientists sifted through broken glass yesterday, museum staff assessed the loss. The items stolen, all late Roman Imperial material dating between the second and fourth centuries AD, include eight engraved or carved semi- precious stones, a ring and a necklace, all bearing Imperial portraits.
A number of silver coins were also taken. Frances Dunkels, a spokeswoman for the museum, said that the specific number of coins would not be known until staff had picked through the wreckage.
The theft took place between 11pm on Thursday and 2am yesterday. Police were unable to say how many people were involved in the robbery, or how they beat the alarms' sensors.
The museum boasts one of the world's most comprehensive collections of Classical antiquities. Andrew Hamilton, a spokesman, said: 'The stolen items were all one-offs and sadly can never be replaced. The jewellery dates from the second century and would have been worn by wealthy patrician Roman women. If the items were melted down their bullion value would be minimal, but these are very traceable items.'
They were taken from the Rome, City and Empire gallery, one of the upper galleries. There is a strong possibility that, like many stolen antiquities, the items will be shipped abroad.