Image copyright AP Image caption The loan of the Ilissos statue to Russia angered many in Greece

The British Museum and UK government have turned down an offer of mediation from the UN's cultural organisation in the Elgin Marbles dispute with Greece.

Campaigners for the return of the Parthenon sculptures to Greece have voiced disappointment at the replies sent from London to Unesco last month.

British ministers said they believed the Greek call for "mediation" was intended simply to secure the return of the Marbles to Athens.

Greece criticised British "negativity".

Culture Minister Nicos Xydakis insisted the dispute was between nations, not museums.

Unesco, through its Intergovernmental Committee for Promoting the Return of Cultural Property, asked the UK in August 2013 to consider Greece's request that it mediate in the dispute over the sculptures - and formally invited Britain to accept mediation last October.

The sculptures have been in the British Museum since the early 19th Century but Greece has been demanding their return for decades.

The Parthenon Marbles

Image copyright EPA Image caption Parthenon Gallery in the Acropolis Museum.

Friezes and pediment figures which decorated the Parthenon temple in Athens, built 447-432 BC

Many were removed by agents of the British diplomat Lord Elgin in the early 19th Century, and eventually sold to the British Museum

Most of the surviving sculptures are roughly equally divided between London and Athens

The new Acropolis Museum (above) opened in Athens in 2009. It is designed to display all the surviving sculptures, in their original layout

In a letter to Unesco on 26 March this year, Culture Minister Ed Vaizey and Europe Minister David Lidington wrote: "We have seen nothing to suggest that Greece's purpose in seeking mediation on this issue is anything other than to achieve the permanent transfer of the Parthenon sculptures now in the British Museum to Greece and on terms that would deny the British Museum's right of ownership."

The ministers insisted that the sculptures were legally acquired by UK ambassador Lord Elgin "under the laws pertaining at the time and the trustees of the British Museum have had clear legal title to the sculptures since 1816".

'World public benefit'

Writing on the same day to Unesco, Sir Richard Lambert, chairman of the British Museum's trustees, said that the museum "would wish always to align itself with Unesco's purposes in the preservation and safeguarding of the world's endangered cultural heritage".

He wrote: "However, the surviving Parthenon Sculptures, carefully preserved in a number of European museums, clearly do not fall into this category."

"The trustees of the British Museum hold them not only for the British people, but for the benefit of the world public."

The best way forward, he said, was for the British Museum "to collaborate directly with other museums and cultural institutions, not just in Greece but across the world".

He cited the recent loan of the statue of the god Ilissos, one of the Elgin Marbles, to the Hermitage museum in St Petersburg, and loans of objects to museums in Greece.

Greece wants the Parthenon sculptures in London to be permanently displayed in the specially designed Acropolis Museum in Athens.

Culture minister Nicos Xydakis expressed sadness at Britain's stance and rejected "the continuing effort to downgrade an international issue to a dispute between museums."

Eddie O'Hara, chairman of the British Committee for the Reunification of the Parthenon Marbles, called the British reply a "sophisticated diversionary tactic" but said it would not "divert the public's thirst to see the sculptures from the Parthenon reunited in the Acropolis Museum".