Athens has vowed to use “every means” in its quest to persuade London to relinquish the Parthenon sculptures, with a campaign that will focus on winning over the hearts and minds of Britons. Far from being discouraged by Boris Johnson’s refusal on Tuesday to engage in intergovernmental talks over the demand for the return of the 5th century BC artwork, the Greek prime minister, Kyriakos Mitsotakis, appeared to be buoyed by his visit to the UK. “My intention is to continue working hard until their final return to the Acropolis Museum,” he told an audience gathered at the Science Museum in London within an hour of meeting his counterpart. On Wednesday Greek officials downplayed Johnson’s insistence that the issue was a matter for the British Museum to resolve, calling the leader’s stance “utterly predictable”. Mitsotakis is the first Greek prime minister to have formally raised the Parthenon marbles at Downing Street. Echoing Mitsotakis’ conviction that the campaign should now prioritise UK citizens, the officials instead voiced glee at the reaction of TV viewers to the Greek prime minister’s plea for the marbles’ return on the show Good Morning Britain. The show’s anchors later said the station had been inundated with tweets expressing support for Mitsotakis. “It will be British public opinion that decisively tips the scales in favour of the just Greek demand,” said one member of the visiting delegation. The removal of the antiquities has been contentious ever since they were ripped from the Parthenon more than 200 years ago under the orders of Lord Elgin, London’s ambassador to the Ottoman empire. When bankruptcy hit, the diplomat sold the masterpieces to the British Museum in 1816. The museum now exhibits 80 of the sculptures, although public viewing has been off limits because of the pandemic and maintenance works for nearly a year. Most of the rest of the frieze, which adorned the Acropolis’ central temple and is viewed as the high point of classical art, is displayed in a purpose-built museum at the foot of the monument in Athens. Eight other institutions across Europe similarly house pieces. Speaking of the need for the marbles to be seen in their entirety in Athens, Mitsotakis insisted their return would be “a fantastic statement” for the global Britain that Johnson envisaged. During the Downing Street talks Mitsotakis applauded his British counterpart as a “true philhellene” with Greek officials subsequently suggesting Johnson had been in favour of the antiquities’ return when, as head of the Oxford Union in 1986, he invited Melina Mercouri, Athens’ first female culture minister, to raise the issue for debate. She won the vote. Greece has also been emboldened by the changing climate towards cultural patrimony and a recent Unesco decision making it clear that the bitter dispute should be resolved at government level and not via the British museum. Mitsotakis has repeatedly described the sculptures as the most important symbolic link between modern Greeks and their ancestors. He used his London visit to emphasise the headway made on disputed cultural property. “Museums around the world are increasingly working to share, return, reunite or lend exhibits on an unprecedented scale,” he said in his speech at the Science Museum. Athens has offered to exchange treasures that have never before left Greece, as part of rotating exhibitions the British Museum could stage in return for the masterpieces. But Tasos Hadjigeorgiou, a Greek MP who was part of the visiting delegation, denied reports that specific artefacts, including Agamemnon’s gold mask, was on a list of treasures that the government was willing to give in return for the antiquities.