One of the city's oldest artefacts has been taken off display amid rumours of security concerns.

The Amber Cup, a 3,000 year-old bronze age relic discovered during excavations in Hove in 1857, has been removed from Hove Musuem and placed into secure storage.

Archaeologists yesterday spoke of their concern that high insurance and security costs were persuading the city to hide away items which should on display for educational purposes.

Members of the Brighton and Hove Archaeological Society said the Amber Cup was a particularly rare item which the British Museum and others would be interested in having if the city did not want it.

Society member Linda Robinson said: "It's very sad that it has been taken away from the public. It should be a centre piece for the museum, it tells us a lot about the history of this area."

The artefact resembles a modern teacup but is intricately carved from a single piece of solid amber, believed to have originally come from northern Europe.

It was discovered while a large round burial mound, known as Hove Barrow, was being excavated at the area which is now Palmeira Avenue.

The cup was inside a nine-foot oak coffin, carved from a single tree trunk, which also contained skeletal remains, a whetstone, a bronze dagger and an axe hammer.

Archaeologists used radiocarbon dating to date it as 1,500BC.

Mrs Robinson said society members had been told the Amber Cup was originally taken off display to keep it secure while roof repairs were being carried out at the museum.

However it has not been returned since the works were finished and no date has yet been given for it to be back in place.

The museum service has been under pressure to improve security since the theft of jewellery worth £25,000 from displays in the Royal Pavilion in 2007.

Brighton and Hove City Council yesterday confirmed its museum service was keeping the Amber Cup in secure storage.

A council spokeswoman said: "It has been taken off display for conservation reasons. It will go back at some stage but we are not able to say when at present."

She said the council would not publish any details of the security and insurance costs for the cup, adding that they formed part of its overall fees.

Councillor Melanie Davis, the opposition Labour spokeswoman for culture, said the council should be prioritising making the most of its rare items ahead of other projects, like the recent installation of artwork in shop windows.

She will question culture cabinet member David Smith about the issue at a meeting next month.

She said: "This is a terrible loss for Hove and I simply fail to see why this of all pieces has been put away."