The Elgin Marbles are in the UK in the National History Museum but there is a long-running dispute over where the ancient sculptures – also known as the Parthenon Sculptures – should be housed.
The Greek prime minister is meeting Keir Starmer on Tuesday, leading to many speculating whether the matter would be discussed by the leaders.
However, Downing Street has said that the Elgin Marbles were not on the agenda for discussion.
Kyriakos Mitsotakis is visiting No 10 in what is his first official visit to the UK since a quarrel with the previous government over the ownership of the ancient marbles.
But what are they? And what have the issues been?
What are the Elgin Marbles?
The Elgin Marbles are a collection of Ancient Greek sculptures from the Parthenon as well as other structures from the Acropolis of Athens.
The marbles previously made up around half of the 160-metre frieze at the Parthenon, which is regarded as one of the world's greatest cultural monuments.
There are 17 sculptures in total which are 2,500 years old. Their name, as well as their current location, has been a source of controversy for years.
Why are they in the UK?
British diplomat Lord Elgin was the ambassador to the Ottoman Empire, which then ruled Greece, in the early 19th century. He oversaw removal and shipping to the UK of the marbles in 170 crates and claimed he was given permission to take them.
He sold them to the UK government in 1816 before the marbles were passed into the trusteeship of the British Museum, where they have remained ever since.
What has Greece said?
Greece has long maintained that the marbles were illegally removed from their place atop Athens’s Acropolis during a period of foreign occupation and has long demanded the return of them.
But the British Government and the British Museum reject Greece’s claim that it owns them, and the marbles remain on display in the museum – where they have been for 200 years.
Greece previously asked for the artefacts back and said they were “prepared to fill the void” left by the marbles and would organise rotating exhibitions of “important antiquities” in return.
What has Keir Starmer said?
A spokesman for the prime minister said the meeting this week was not about the marbles but instead about matters affecting the entire world. He said: “It’s not going to be on the prime minister’s agenda. His focus will be on support for Ukraine, the urgent need for a ceasefire in Gaza.”
He added: “Our position on the Elgin Marbles has not changed.
“It remains a matter for the British Museum, and the Government has no plans to change the law to permit a permanent move of the Parthenon Sculptures.”
