HRH Charles discussed the 12 million pound restoration work on his father Prince Philip's family palace with the Greek prime minister

King Charles met with Greek Prime Minister Kyriakos Mitsotakis and his wife Mareva Grabovski at Windsor Castle, where they discussed the £12.3 million renovation of Prince Philip's ancestral palace in Greece.

Tatoi Palace, 17 miles north of Athens, was once the home of the Greek royal family but was left in a ruined state after a military coup in 1973. However, there are now plans to turn it into a museum as part of a joint project between the UK and Greece.

Prince Charles visited the palace last year, where his grandfather is buried, as part of the 200th anniversary of the Greek War of Independence. The Prince's Foundation is advising the Greek government on the restoration of the historic palace.

King Charles appeared pleased and smiling during his meeting with Prime Minister Mitsotakis. King Constantine of Greece stated that the plans will build on the £45 million restoration of Dumfries House in Ayrshire, carried out with King Charles' involvement. He also said that they want to use this example as best practice.

King Charles was interviewed by the makers of 'Royal Grand Design', which will air tomorrow on ITV, where he spoke about his efforts to restore the Ayrshire estate. He said the project was a "terrible risk" that nearly bankrupted him as Prince of Wales, but proved to be worth it. King Charles added that he knew it was a deprived area and he wanted to use it as an example of what he had always believed in - restoring cultural heritage.

During the meeting, King Charles wore a gray suit, white shirt and dark brogues. Mr. Mitsotakis chose similar formal attire, wearing a dark blue suit with a single-breasted jacket, white shirt and royal blue tie.

According to some Greek media, one of the topics of discussion at the meeting could be improving the management and preservation of the Tatoi estate, which used to be the summer residence of the Greek royal family. The meeting follows reports this year that Mr. Mitsotakis hopes King Charles will help him return the Elgin Marbles to Athens. The 2,500-year-old marbles were removed from the Parthenon between 1801 and 1812 by Lord Elgin, the ambassador to the Ottoman Empire. The Greeks claim they were stolen, but the 1963 British Museum Act prohibits the transfer of ownership of artifacts from the museum.

In October, Mr. Mitsotakis told The Sunday Times that he has a "good personal relationship" with King Charles and believes the latter supports him. The king, he said, has a "Greek heritage that he values" and added that "the mood in Britain is changing."

It has also been revealed that Greek businessman John Lefas is investing millions of pounds to send British MPs to Athens and pressure them to change British law to allow the return of the marbles. Lord Vaizey, a former Tory culture minister, has already made the trip as part of the Parthenon project, The Sunday Telegraph reports.