The incident comes after Greek prime minister Kyriakos Mitsotakis used an interview ahead of anticipated talks to push for the return of the Elgin Marbles, saying the current situation was like the Mona Lisa painting being cut in half.
He was offered a meeting with Deputy Prime Minister Oliver Dowden instead but turned that down.
– What are the Elgin Marbles?
The Elgin Marbles, also known as the Parthenon Sculptures, once adorned the Parthenon atop the Acropolis in Athens.
The 520ft frieze ran around the outer walls of the Parthenon, dedicated to Athena, goddess of wisdom.
Carved between 447-432 BC, the frieze and other sculptures remained largely intact until the temple, which was being used by a Turkish garrison as a gunpowder store, was blown up during a siege in 1687.
– Why are the statues in the British Museum?
Much was lost following the explosion in 1687 and about half the surviving works were removed by British diplomat Lord Elgin in the early 19th century, while Athens was still under the rule of the Ottoman Empire.
They have been in the British Museum since 1816.
Most of the other works are in the Acropolis Museum, with scattered fragments in Paris, Copenhagen, Munich and Wuerzburg in Germany, and Vienna.
-Why has Greece demanded the marbles be returned?
Athens has been campaigning for decades for the return of the artefacts.
The country has long claimed they were illegally acquired during a period of foreign occupation.
In 2009, the Acropolis Museum was built in Athens to house the sculptures that remain in Greece alongside other treasures, providing an in-depth view of the ancient history of the Acropolis and its surrounding religious sanctuaries and civic structures.
The museum contains a gallery dedicated to the marble sculptures, where the missing parts have been replaced by plaster casts.
Mr Mitsotakis has called for the marbles to be returned to Greece on many occasions, even offering to loan some of his country’s other treasures to the British Museum in exchange.
-What has Britain’s stance been on the Marbles?
British officials have rebuffed repeated demands for the objects to be returned to Greece.
The 1963 British Museum Act prevents the institution giving away objects from its collection except in very limited circumstances.
Prime Minister Rishi Sunak previously said there are “no plans” to change the law, which blocks the Elgin items from being given to Greece.
Mr Sunak said the UK had “cared for” the sculptures in the British Museum for generations and that they were “shared with the world” at the London site.
British Museum chairman George Osborne, a former chancellor, has previously said he is exploring ways for the Elgin Marbles to be displayed in Greece, with speculation that this could involve a loan deal in which part of the set would be sent to Athens.
– What other objects have been controversial in Britain?
The British Museum has a number of contested objects in its collection such as large stone statues from Easter Island and its Benin Bronzes.
The museum received a written request for the return of “Nigerian antiquities” from Nigeria’s Federal Ministry of Information and Culture in October 2021.
Representatives of the Benin Royal Palace have also spoken publicly about the Benin collections being returned.
Last year, the Horniman Museum in south-east London agreed to return ownership of a looted collection of 72 treasured artefacts to Nigeria, including its Benin Bronzes, because it is the “moral and appropriate” thing to do.