The long-running dispute between Greece and Britain over the Parthenon Marbles has seen a bitter escalation after British Prime Minister Rishi Sunak cancelled a meeting with his counterpart Kyriakos Mitsotakis. A series of 2,500-year-old friezes and statues housed in the British Museum were taken from Athens in the early 19th Century. Athens has long-demanded the sculptures' return - but to no avail.