Greek culture officials are furious after the British Museum refused to take part in talks over the future of the Parthenon Marbles.
It comes after the museum's director Sir Richard Lambert rejected a United Nations' offer to chair talks over the possible return of the Marbles to Athens.
In a letter to UNESCO officials the director said the museum's the trustees had 'decided respectfully to decline this request'.
And British Culture Minister Ed Vaizey also wrote to UNESCO to rule out any possibility of talks. The letter said: "The fact remains that the Parthenon sculptures in the British Museum were legally acquired by 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."
Greece has been called for the return of the 2,500-year-old marbles to the Parthenon for more than 30 years, but so far without success.
They have been under dispute since they were illegally removed and taken out of Greece by the Earl of Elgin in 1803 and later installed in the British Museum.
Sir Richard Lambert has instead offered talks on proposed loans to the Acropolis Museum, highlighting previous joint ventures between the museums.
He said: "We would invite our colleagues in Greek museums to continue to work with us and to explore new ways of enabling the whole world to see, study and enjoy the sculptures of the Parthenon."
But the Greek response has left little room for compromise. Greek Deputy Culture Minister Nikos Xydakis accused Britain of repeatedly downgrading the 'international issue' into a mere 'problem between museums'.
He added: "The negativity of the British is overwhelming, along with their lack of respect for the role of the mediators."
Things haven't been helped by news that the British Museum is again planning to loan parts of the Parthenon Marbles to museums across the world as early as July this year.
The fragility of the marbles and fear of damage being caused by transport to Greece has previously been an excuse for failing to return the sculptures to Greece.
There were angry scenes in Athens last year when a statue of the river god Ilissos was secretly shipped to the State Hermitage Museum in St Petersburg in Russia.
Former Greek Prime Minister Antonis Samaras dubbed the decision to 'loan' a sculpture to the State Hermitage Museum to celebrate its 250th anniversary is an 'affront' to the Greek people.
He said at the time that the 'Parthenon and its sculptures have been looted. The value of the sculptures is priceless.'
Greece's campaign for their return won the support of lawyer Amal Alamuddin Clooney, recently married to actor George Clooney, who has held meetings with ministers over possible legal action.
Greece had already threatened international legal action to have the treasures returned but was advised to await the the outcome of possible talks between UNESCO and Britain on the dispute after the UNESCO offered to act as a mediator.
It remains to be seen if the future home of the Parthenon Marbles will be decided in an international court.
The British Committee for the Reunification of the Parthenon Marbles Eddie O'Hara described the UK government's decision as 'deeply disappointing' adding that the offer of a loan would be considered by the Greeks as little more than an insult.