By Henry Zeffman, Harrison Jones & Chris Mason
Rishi Sunak cancelled his meeting with the Greek prime minister after it was felt a promise not to publicly discuss the Parthenon Sculptures was broken, Downing Street said.
Kyriakos Mitsotakis told the BBC on Sunday he wanted the artefacts – also known as the Elgin Marbles – returned from the British Museum to Greece.
The meeting was scrapped on Monday at late notice.
A Greek government source denied assurances were given to the UK.